Organic Chemistry Nomenclature

Welcome back to Educator.0000

We've already had a brief introduction on how to name alkanes; some basic IUPAC rules; methane, ethane, propane, and so on.0003

Let's take a look at some more complex alkanes and cycloalkanes and a variety of other functional groups we will encounter.0010

If we have a ring in a compound, we call those cycloalkanes; we simply take the name of that alkane and we put the prefix cyclo- before it to indicate that those carbons are forming a ring.0018

If there is a single group that is attached, if it is a mono-substituted ring, then we assume that the point of attachment is carbon number 1, defined as carbon number 1.0031

Because when we have a carbon chain... when we have a carbon chain, we have to decide which end to number from.0040

But when the carbons are in a ring, any carbon within the ring can be carbon number 1; we have to decide which one to assign as number 1.0046

For this first example, we have a five-membered ring; a five carbon alkane is called pentane; so this is called cyclopentane.0054

Then we take... that is our parent; then we alphabetize and number our substituents as usual and put them out front.0066

We have a two carbon chain here; that is an ethyl group; this is simply called ethylcyclopentane, all one word.0073

There is no number that needs to be drawn because any place you put the ethyl on that ring, you are going to get the same compound; so this is called ethylcyclopentane.0082

If we have two more groups, now we have to decide which carbon is defined as carbon number 1.0092

If there is one carbon with two groups on there, then that would be the best place to assign as number 1 because then we would have two groups at position number 1.0097

Remember we always want to get the lowest possible numbers that we can; so we will define that as carbon number 1.0107

Now we have to decide, are we going to number in a clockwise fashion or counterclockwise?0112

We want to number in the direction closest to the next substituent so that that substituent gets as low a number as possible.0117

Let's number here in a counterclockwise, this direction; two, three, four, five, six; this is a cyclohexane parent; cyclohexane.0123

We have a fluoro and a methyl and then this group is a little more complex than a simple methyl, ethyl, propyl, that sort of thing; how would we name that?0139

We have some instruction here; to name a complex substituent, we need to define the point of attachment to the parent as carbon number 1.0151

Then we perform a second, like a little mini IUPAC, to describe the name of that complex group.0159

For example, this is the group that... this is the point of attachment; so this has to be described as carbon number 1 for this substituent.0165

Then we ask what is the longest carbon chain from that point on?--we see that we can have a three carbon chain here; this is actually a propyl group.0174

But it is more than just a propyl; what does it have on carbon 1?--it has a methyl group; we are going to describe this as a... this whole group is described as a 1-methylpropyl.0184

That is how we will handle more complex substituents; now let's alphabetize these and list them in the proper order; the fluoro comes first so we have a 1-fluoro.0200

Then methyl comes before methylpropyl; just like if you look that up in the dictionary, the shorter word would come next; we have a 1-methyl.0211

Then at carbon 3, we have this big whole group; what we do is we write a 3, and then in parentheses, we write this big name of the complex group.0220

Let's see if I can not completely run out of room; we have a 1-methylpropylcyclohexane.0229

How about this last case?--we have a four-membered ring; we call that cyclobutane.0241

Here we have two groups; we have to decide now which one should be carbon 1 because we could either have 1,2 or 1,2; we would get the same set of numbers either way that we numbered it.0250

In that case what we do is the carbon bearing the group that comes first alphabetically is assigned number 1.0263

That way the substituents are listed alphabetically and the numbers are listed in increasing order.0271

What we have here is a methyl; then this is going to be a longer word; we will have that next.0277

You know what?--let's make this an ethyl... sorry... so this comes first alphabetically; we will just change that.0285

This is... we will do one and two and three and four; this is another complex substituent that we are going to have to name.0293

It looks like a t-butyl group; that would be nice if we were allowed to use a common name; we could just describe it as a t-butyl.0302

But an IUPAC name can't use that term; so instead we go through our rules again; now this is carbon number 1; what is the longest carbon chain from that point on?0308

No matter which direction you go, the most you can have is two carbons; so this is actually an ethyl group.0320

But it not just an ethyl; it has a methyl here on carbon 1 and another methyl on carbon 1; what we are going to call this is a 1,1-dimethylethyl.0327

This is the IUPAC name for the t-butyl group; it is a 1,1-dimethylethyl; and where was this whole group?--this whole group was on position 2.0345

On position 1, we had an ethyl; we could double check, see how we alphabetized e- comes before m-; when we go to alphabetize, we ignore the prefixes like di- and tri-.0357

So we have a 1-ethyl-2-(1,1-dimethylethyl)cyclobutane; we have the ring for the cyclo; we have the four carbons.0372

Bit by bit, step by step, in a systematic way, we are going to build these complex names up.0383

If we have a carbon-carbon double bond in a structure, those compounds are called alkenes; the way we are going to name them is we are going to look for the longest carbon chain.0390

But that longest carbon chain must include both carbons of the carbon-carbon double bond; it is no longer just where is the longest carbon chain throughout the whole structure?0399

Now that we have a functional group in the molecule, we need to incorporate that functional group into the parent; so the longest carbon chain must contain both carbons of the carbon-carbon double bond.0407

Then we are going to number from the end that is closer to the carbon-carbon double bond so that the double bond will get the lowest number possible.0418

After doing that, what we are going to do is we are going to take the ?a in the word alkane, methane, ethane, propane, butane, and we are going to change it to an -e.0427

We are going to call it an alkene instead; and we are going to put a number out front that tells the reader where the double bond starts--what is the first carbon of that carbon-carbon double bond.0436

We are going to call it a #-alkene or you can insert that number inside the name; this is actually the preferred way for IUPAC.0447

But I think it is a little more difficult for beginning students to look at that convention.0456

For example, our simplest alkene is a two-carbon alkene; he has a common name; this is called ethylene; ethylene is a gas that is generated by fruits in the ripening process.0463

Ethylene is actually sprayed on fruit to help them ripen when they are picked earlier for packaging and for handling.0473

This is commonly known as ethylene gas; but the IUPAC name, it would be an ethane derivative because it is two carbons; instead of calling it ethane, we call it ethene.0481

Not a big difference between the common name and the IUPAC name; but the IUPAC name is ethene; this tells the reader... that E tells the reader that there is a double bond in this molecule.0496

In this case, I don't need to indicate where the double bond is because there is only one place for it to be--connecting those two carbons.0506

This compound is commonly known as allyl chloride because you have a chlorine that is allylic--next to a double bond.0512

It is known as allyl chloride; but let's do its IUPAC name; we have our three carbon chain is right here; that is our only possibility for our longest carbon chain.0519

When we go to number it, we are going to number it from the end closest to the double bond; we will start from this end; one, two, three.0528

Three carbons means it is a propane derivative; because of the double bond, we call it propene; this is 1-propene.0538

We are going to indicate the first carbon of the carbon-carbon double bond; this implies that there is double bond starting at 1 and going to 2.0547

What else do we have on here?--we have a chloro group at carbon 3; so this is 3-chloro-1-propene; remember there is dashes between numbers and letters.0555

Sometimes we leave off the 1; in this case, that might be implied; but it is a really good habit to leave that 1 in there.0569

We don't want to make that assumption then make a mistake; so this would be the best name for that.0576

How about this case?--where is our longest carbon chain that contains both carbons of the double bond?0582

It looks like we will come across here but then we will move down in this direction because that would be a longer chain than over here.0588

How are we going to number it?--if we numbered it from here, our double bond would start at carbon 2.0596

If we numbered it from here--one, two, three four, it wouldn't start till carbon number 4.0601

We would rather have it be at carbon 2; one, two, three, four, five, six; a six carbon alkene is going to be called hexene; it is a 2-hexene.0605

By circling off and blocking off the parent, it is very easy for me to see what other groups are attached.0622

We still have this two-carbon group; that is called an ethyl group; at carbon 3, we have an ethyl.0628

How about this next case?--our longest carbon chain would be this one; but the longest carbon chain containing the carbon-carbon double bond would be down here.0638

We have to make sure to include that; and how long is that?--one, two, three, four, five, six, seven, eight carbons; that is an octane derivative; we are going to call this 1-octene.0647

At carbon 2, we have a one, two, three carbon chain; that is a 3-propyl; 3-propyl-1-octene.0663

We can incorporate a double bond into a cyclic structure as well; remember, with a ring, we have to decide where to start numbering our carbon chain.0673

One of the double bond carbons is going to be carbon number 1; we are going to have to number through the carbon chain and then continue on to also give the substituent the lowest possible number.0685

If I numbered from here, one, two, three, four, five, six, the substituent wouldn't be until position 6.0695

If I numbered this way, one, two, three, I get the lowest number for the double bond; that has to be at carbon 1; then I also get the substituent at the lowest number.0702

Four, five, six; this is a six-membered ring; we would call that cyclohexane because it is a ring; because it has a double bond, we call it cyclohexene.0712

Where is our group?--what is this group called?--the benzene ring is called a phenyl group; we have a 3-phenylcyclohexene.0725

Here is a case where we really don't need the number; the double bond has to be between carbons 1 and 2; that is how you define a ring.0734

There is no other place to put the double bond since that is our highest priority; if you want to put that in there just to be safe, that probably won't hurt if you want.0741

What if we have two double bond?--if we have two double bonds, we are going to indicate both numbers of where the double bonds start.0751

We are going to call it a diene or a triene or a tetraene and so on; so we are going to include that, we are going to put that in there.0758

Again, we want to give our double bonds the lowest possible number; and I need to give both double bonds the lowest possible number.0768

The only way to number this to give the double bonds the lowest possible number would be as so; one, two, three, four, five.0778

What do we have on carbon 5?--we have a bromo; we have another 5-bromo; we are going to call that a 5,5-dibromo... a 5,5-dibromo.0787

Then at carbon 1 and carbon 3 is where we have our double bond starting; this is a 1,3-cyclopentadiene.0797

Notice we stick that -e back in; it would be called cyclopentene, but when we have the diene or the triene, we put the -a back in just because it is easier to read that way.0812

So it is called cyclopentadiene or hexadiene or some such thing.0822

Another thing that we need to be concerned with with double bonds is the fact that we can have stereochemistry associated with the double bond.0830

Where if we have two groups... remember we have cis or trans as a relationship that those double bonds can have; all the examples here don't have that shown.0837

This molecule can have cis-trans isomerism, but I haven't shown one particular stereoisomer; I haven't shown the geometry of this molecule.0848

I have drawn this as a linear molecule with these bonds hanging straight down; we wouldn't be able to tell which stereoisomer I was dealing with here.0857

When you have a double bond in a ring, in a five or six-membered ring, that double bond has to be cis.0866

Those two alkyl groups have to be pointing in the same direction in order for them to reach each other and form a small ring.0872

So this must be cis if you are looking at a seven or fewer... for small rings, let's just say... for small rings.0879

So we don't say that it is cis-cyclohexane because there is no such thing as trans-cyclohexane; it would be impossible to build that.0892

Let's take a look at some examples that do have stereochemistry involved because we are going to want to include that as part of the name.0901

If you have an alkene simply with two groups and two hydrogens, then we could describe those two groups as being cis or trans.0909

Cis means they are on the same side; trans means they are on opposite sides.0917

For example, we have an alkene here; let's number from the end closest to the alkene; one, two, three, four, five, six; this is hexene; this is 2-hexene.0926

But one particular stereoisomer is shown of 2-hexene, where the two alkyl groups are pointing on the same side; we are going to describe this as cis-2-hexene.0937

We are going to put that stereochemistry all the way out in front of the name to describe the stereochemistry of the double bond.0948

Here is another example; we have this in a ring; one, two, three, four, five, six, seven, eight, nine, ten; this is a ten-membered ring.0955

We would call this a cyclodecane if it was an alkane; because it has a double bond, we call it cyclodecene.0966

In this case now, we have one carbon group pointing this way and one pointing this way... let's write the name first, sorry... cyclodecene.0975

But in this case, the two carbon groups are not pointing in the same direction; they are pointing in opposite directions.0989

If you want to look at the hydrogens to confirm that, you drawn in those hydrogens for those trigonal planar carbons.0994

You see that in fact they are pointing in opposite directions; so this is an example of trans-cyclodecene.0999

If we had looked at this molecule instead, if the double bond were here, this would be an example of cis-cyclodecene because those two carbon groups are pointing in the same direction.1006

When stereoisomers can exist, we need to look carefully at the three-dimensional picture that is shown to decide which stereoisomer it is that we are trying to name.1020

Here is another example; now we have three alkenes; let's number from here so we get the lowest numbers possible--one, two, three, four, five, six, seven.1031

Seven carbons is a heptane; when we have three double bonds, we call this heptatriene; where are those three double bonds?--they start at 1 and 3 and 6.1041

If it is a triene, we need to have three numbers out front; the triene, one, two, three, tells us where those three double bonds are.1057

Is there any stereochemistry in this problem?--there can't be any stereochemistry on this first or this last one because there is only one group attached.1068

But look at this middle one; there are two groups attached; what is the arrangement of those two groups?--they are on opposite sides; this is trans.1076

Sometimes we might miss that; if it is a line drawing and it is obviously drawn in the same side, then we might notice that it is cis.1084

But when we leave it in its regular zigzag notation, sometimes we might miss that that must actually be the trans isomer that is shown; this is trans-1,3,6-heptatriene.1090

I don't need to say which double bond is trans because it is the only double bond that can have stereochemistry.1101

If we only have groups, we can use the word cis and trans; if we have more than two groups, the term cis and trans doesn't mean anything more.1108

Cis means the two groups are on the same side; trans means the two groups are on the opposite side; if I have three groups on the alkene, the term cis and trans is now ambiguous.1116

We need to learn new terms to describe those stereochemistries; the new terms we have are going to be E or Z.1125

Z is what means the same side; so if we are similar to cis, we are going to call it Z; and E means opposite sides.1134

Where do these letters come from?--E and Z, they come from German words; if you speak German, you will have no trouble remembering these rules.1149

If you are like me and these words are not familiar to you, then you need some kind of way to remember which is E and which is Z and what do they mean.1156

I have a little mnemonic that I came up with that I will share with you; see if that helps.1165

Here is how we assign it; what we do is we look at one carbon at a time and we assign the priorities to those two carbons.1172

We are going to use the same... we are going to prioritize them based on simply their atomic number.1180

We are comparing a chlorine to a carbon; chlorine has a higher atomic number so chlorine is a higher priority than carbon.1186

Then we go to the second carbon and we do the same ranking; carbon versus hydrogen; carbons wins; it is a higher priority, higher atomic number; that is also number 1.1194

We ranked them 1,2 and 1,2; now what we do is we compare the number 1 groups and we ask: are those number 1 groups on Zis same side?1205

If we say it with a little crazy accent, then we remember that Zis same side means that it is the Z stereochemistry.1215

In other words, since these number 1 priority groups are cisoid to each other, we are going to describe this molecule as being the Z stereochemistry.1221

We put that all the way out in front in parentheses; this is italicized as is the cis and trans are italicized, you see when they are in print; this is going to be called (Z)-2-chloro-2-butene.1230

The other stereoisomer, if I swap the chlorine and the methyl, the chlorine and the CH₃, now you see that my number 1 priority group is here and my number 1 priority group is here.1241

Now they are transoid to each other; we ask: are the higher priority groups on Zis same side?--they are not; now it is the opposite of Z; it is E.1250

We need to remember what both of those names are; of course, the more you work with these, the more you will become familiar with which is which; this would be called the E isomer.1258

Let's just take a look at a couple quick examples here; how would we name this alkene?--the longest chain that contains the double bonds is right here.1267

What side do we number from?--one, two, three; one, two, three; this is a case where we would we have a tie for the double bond.1279

How do we break that tie?--now we want to consider the substituents and try and give them also the lowest possible number.1288

We will number from the end closest to the first substituent; one, two, three; this would be the better direction to go, the correct direction to go.1294

This is a six carbon chain; we call that hexene; the double bond starts at carbon 3 so we call this 3-hexene.1304

What else does it have attached?--we have a methyl and a methyl and a methyl; we group those all together; we call this a 2,3,4-trimethyl.1315

Sorry, I ran out of room here... 2,3,4-trimethyl-3-hexene; which isomer have we shown?1330

Again, I can't... what does the word cis mean here?--or trans?--it has no meaning; we have to define it as E or Z.1336

What we do is we break the double bond in half; we look at one carbon at a time.1343

This carbon... we are comparing a carbon and a carbon; that is a tie; how do we break the tie?--we are going to move the next atom and so on until we find a difference.1348

This has three hydrogens attached; this has another carbon attached; this group wins; this is number 1; this is number 2; in other words, an ethyl beats a methyl.1357

Over here, we have again a tie--carbon versus carbon; but this carbon just has three hydrogens on it while this carbon has two other carbons attached; this is number 1 and this is number 2.1368

Which isomer do we have here?--do we have E or Z?--we compare the number 1 groups; are they on Zis same side?--they are not; they are on opposite sides.1382

We call that the E stereochemistry; that goes all the way out front; we describe this as E.1391

How about last one?--what is our longest carbon chain?--we have to come down in this direction to find the longest carbon chain containing the two carbons.1398

We will number from this end to give the double bond on carbon 2; this is a pentene derivative; it is pentene; it is 2-pentene.1408

We also a chloro and a methyl; who will come first?--we will do alphabetically; 1-chloro-3-methyl.1425

Finally, do we have stereochemistry?--we need to check every time; is there stereochemistry in this case?1436

There is because we have three different groups on here; if I flip these two groups around, it would be a different isomer; it would be a different compound.1441

How do we describe this isomer in its name?--we rank the two groups on carbon 3; we have a methyl and an ethyl; we have done that ranking before; the ethyl is the higher priority.1449

What are the two groups on carbon 2?--we have a carbon and a hydrogen; there is just a hydrogen here; so this chloro substitute group is the higher priority.1461

Here we see our two higher priority groups are on Zis same side; they are on the same side; they are cisoid to each other; we describe it as the Z stereochemistry.1471

When we have a carbon-carbon triple bond in a molecule, we call it an alkyne; we are going to very much follow the same rules we did for alkenes.1488

Except instead of replacing the -a in the alkane, we are going to replace it with a -y instead of with an -e; we are going to name it as an alkyne.1495

Once again, we have to put the number out in front or insert it in the middle to say where the triple bond is on the carbon chain.1505

We are going to try and give the triple bond the lowest number possible; if we had two or three or four alkynes, we would call it a diyne or a triyne or a tetrayne.1514

Let's again look at some simple examples; this is the simplest alkyne; it is called acetylene; that is another fuel; acetylene is what is used in torches, very hot burning fuel.1527

This is called acetylene; its IUPAC name, since it is two carbons, means it is an ethane derivative; we are going to call this ethyne.1537

We are going to call it ethyne or acetylene--is another name that you should be familiar with.1547

The word propargyl means next to a triple bond; just like we use the word allylic to mean next to a double bond; propargyl means it is next to a triple bond.1553

This could commonly be known as propargyl bromide; but let's do its IUPAC; we have a three carbon chain in this case; numbering to give the triple bond the lowest number.1566

This is a propyne derivative; it is 1-propyne; at carbon 3, we have a bromine; we are going to call it 3-bromo; 3-bromo-1-propyne.1576

How about this case?--what is our longest carbon chain?--longest carbon chain will go here and here and don't be fooled by this CH₃ group.1593

I am not going to stop at the end of this carbon chain because my carbon chain is not done; it extends up here.1602

There is actually a one, two, three, four, five, six carbon chain here, with a triple bond at carbon 1; we are going to call that a 1-hexyne... a 1-hexyne.1608

What else do we have?--we have a methyl and we have a phenyl... we have a phenyl; which comes first?--L-M-N-O-P, methyl comes first; so we have a 4-methyl and a 5-phenyl.1621

That is our hexyne; if we have multiple double bonds and triple bonds, our names get pretty ugly pretty quickly.1639

Here we can number one, two, three, four, five, six, seven, eight; it is an octane derivative; but we have a double bond at 1 and 6; it is an octadiene; plus we have a triple bond at carbon 3.1646

Here we have to... because we have two different functional groups in the same molecule, we have to break the name up and insert the number right before the suffix it is modifying.1663

This means I have a triple bond at carbon 3 and my diene is at carbons 1 and 6, starting at 1 and 6.1674

Or you could break up the name more completely and insert the numbers in both cases immediately before the functional group that they are representing, that they are defining.1684

Either one of these is fine; but the one where the numbers are inserted are becoming increasingly more common.1700

If you have to make a choice between an alkene and an alkyne, who gets the lower number?--it is the alkene that wins.1707

In this case, when we look at our longest carbon chain right here, we want to number from this end so that the double bond gets the lowest number possible.1713

Then the triple bond just ends up where it ends up; this is a seven carbon chain; what do we call that?--that is a heptane derivative.1726

But now we have an ?ene and an ?yne; let's break up the name; we have a hept-2-ene and then a 6-yne; hept-2-ene-6-yne.1734

We also have a phenyl group here on 7; we can throw in a 7-phenyl; then that continues all one word hept-2-ene-6-yne.1754

If you an OH on a carbon chain, we are going to describe that molecule as an alcohol; that is going to define the parent chain.1766

It is going to be the carbon containing... the chain which contains the carbon bearing the OH group; and it is going to be named as an alcohol.1776

We will find the longest carbon chain that has the alcohol attached to it; and we are going to number from the end closest to that alcohol so that that alcohol gets the lowest possible number.1785

What we are going to do is we are going to drop the ?e at the end of the name and we are going to add a new suffix; we are going to put the ?ol at the end of it.1795

So it is going to be called methanol, ethanol, propanol, and so on.1805

We need to also put a number out in front to tell the reader where along the carbon chain that OH group resides.1809

Once again, you can sometimes see the number inserted immediately preceding the suffix so that it is no question to what the number refers.1817

For example, this looks like the isopropyl group, when we have three groups and attached at the middle; this is called isopropyl alcohol.1828

You may have heard of that compound; that is used as rubbing alcohol; it is an astringent; you can use that as a cleaning agent.1835

You might find that in your medicine cabinet for facial cleaners and such.1842

Isopropyl alcohol, that is the common name for this; its IUPAC name would follow the rules described above--longest carbon chain containing the OH group; the OH defines our parent.1847

It doesn't matter in this case which way we number it because both of them would put the carbon bearing the OH as the carbon 2.1862

We are going to call this 2... instead of propane, it is propanol... propanol.1870

We dropped the -e and we replaced it with an ?ol; the number 2 tell us where that alcohol is, where that hydroxyl group, that OH group is.1876

Here is another example; we have a four carbon chain; now we would have to number it in this direction to give the OH the lowest possible number.1887

This is called a... it is four carbons so it is called 2-butanol; but this also has a common name.1895

What does this arrangement look like?--when we have a four carbon chain and we've attached something at the second carbon, the secondary carbon?--we call this sec-butyl.1902

This could also be called sec-butyl alcohol; those common names just give us a picture so quickly that it is really useful to be familiar with them.1911

How about this case?--we have a couple OHs; this is where we are going to now call it a diol; our longest carbon chain must contain both OHs.1926

Once we find an OH on our structure, we have to... that defines our parent carbon chain; it is no longer just about finding the longest carbon chain; that is if all we have is an alkane.1937

Let's go up here; it looks like that is the longest carbon chain that contains our two OHs.1948

We will number it to the end closest to the first OH; we will number down here one, two, three, four, five so that we have an OH at carbon 1.1955

Let's see, a five carbon alkane is called pentane; with one OH, we would call it pentanol; with two OHs, we call it pentane diol.1965

Notice we add the -e back in; we actually at the ?e back in because it is easier to read that way than just saying pentandiol; that would be difficult; so it is called pentane diol.1975

We have to tell everyone where these OHs are; they are at 1 and 4; these numbers tell us where to find the OHs.1989

What else do I have on this chain?--I have a 3-methyl; and I have a one, two, three, four, five, six; I have a hexyl; that comes first; we have a 2-hexyl and a 3-methyl... 1,4-pentane diol.2002

Once I see an OH on our chain, that is going to have the highest priority number; I no longer care where the double bond or triple bond is; I always want to make sure my OH gets the lowest possible number.2023

For example, in this ring, since any carbon can be carbon 1, we have to decide which is carbon 1; it is the carbon bearing the OH; that must be carbon 1.2034

Then we are going to number again either clockwise or counterclockwise to take care of the rest of the functional groups.2044

Of course, now we will number in a counterclockwise direction so that the double bond gets the lowest possible number.2049

This molecule is called 2-cyclohexene-1-ol; the 2 refers to the double bond and the 1 refers to the OH group.2056

Again, when you have two functional groups with numbers on them, it is sometimes a little clearer to break up the name and insert both numbers directly into the name.2066

But you clearly have to break it up a little bit; otherwise, you can't just put the 2 and the 1 out in the front, because then you wouldn't know which number describes which functional group.2077

We have to break up the name at least this much; and you insert a number immediately before the suffix.2085

How about this next one?--longest carbon chain is right here; how do we number it?--which end do we number it from?2094

I don't care what number the triple bond gets; I care instead what number the OH gets so I am going to number from this direction; one, two, three, four, five.2104

Let's see, five carbons would be a pentane; the triple bond makes it a pentyne... pentyne; this is where the triple bond changes this middle letter.2116

Because of the OH, we call it a pentyne-ol; let's put the 2 in here so we know where that alcohol group is; and the triple bond was at carbon 4; this is 4-pentyne-2-ol.2130

Or you could say pent-4-yne; the triple bond starts at carbon 4; -2-ol; the suffix always goes at the end; the ?ol is always the very last thing that you have.2145

We take care of all this parent stuff; then we list out front everything else that is attached.2159

We have already handled the OH; we've already handled the triple bond; the only thing left is this methyl group at carbon 2; we alphabetize all those, put them out in front.2164

Notice how we keep building on these systematic IUPAC rules; so it is really important to get that foundation down of your alkanes.2175

Then gradually build on them with each new functional group so that you can see how they work together when you have multiple functional groups in the same structure.2183

If you have an ether in your compound, an ether means that we have an oxygen attached to two carbons.2194

An ether is not something that changes the parent name like an alcohol does; we are not going to learn a new suffix for it.2201

Instead, it is simply a substituent that you might find attached to the parent; it is just a group; how do we name that group?2208

If we have an OR group hanging off of a parent, normally we would call that R group, have a -yl ending like a methyl, ethyl, propyl.2215

What we are going to do is we are going to change that -yl and we are going to make it ?oxy instead; instead of ethyl, we have ethoxy; so we have ethoxy, propoxy, butoxy, and so on.2224

If we have very simple ethers, sometimes we just use common names by listing the two alkyl groups on either side; again it is nice to be familiar with the common names; but that is not IUPAC.2237

For example, this could be named isobutyl ethyl ether as a common name because it has an isobutyl on one side, has an ethyl on the other side.2250

That is one name for this ether; but let's see how we would do it by IUPAC.2260

With an ether, what we have to decide is of the two alkyl groups on either side, or the two carbon chains on either side of the oxygen, which one is going to be the parent.2264

We are going to look for either one that has a functional group on it or one that is a longer carbon chain; here they are both just alkanes so we will go on this side with the longest carbon chain.2272

Here is our longest carbon chain; now it is an alkane; so we treat it like any alkane; we are going to number it so that the substituents get the lowest possible number.2283

We will number from this end; one, two, three; this is a propane derivative; what does that propane have on it?--it has a methyl.2291

Then this group, what do we call this group?--it has one, two carbons, plus an oxygen; we are going to call that an ethoxy group; this is an ethoxy group.2301

Then we alphabetize it just as usual; ethoxy comes before methyl; so we have a 1-ethyoxy-2-methyl; pretty complicated name for this molecule.2312

You can see why we might prefer to just call it isobutyl ethyl ether because that gives a much quicker picture to those who are familiar with those common names.2324

How about this guy... I'm sorry, I skipped some information on that previous slide; it pointed out that these aromatic groups, the benzene with an OH is called phenol.2336

This parent could be named as phenol; the OH is defined as carbon number 1; in the 3 position, we have a methoxy group; this is called 3-methoxyphenol.2351

This compound is called diethyl ether as its common name; again just two ethyl groups attached to an oxygen; that is usually how we describe this molecule.2370

But what would its IUPAC name be?--you have to pick one of those ethyl groups to be your parent; it is no longer an ethyl group; it is now ethane as your parent.2379

What does that ethane have attached to it?--it has an ethoxy group; ethoxyethane.2391

What if we have an OH and an ether again?--how do we decide who has priority and where do we go for the parent chain?2405

Again, as soon as you see that OH, that means your molecule is an alcohol and that carbon attached to that OH has to be your parent.2413

Let's define that as our parent; here is our carbon chain containing the OH group; we will number it from this direction to give the OH the lowest possible number.2421

This is a 3-hexanol... 3-hexanol because it has an OH group; what are we going to call this group?--again, this is not a simple methyl, ethyl, propyl.2436

What we need to do is we need to figure out how to name this; what we are going to do is our little mini IUPAC here.2452

Remember, by definition, the point of attachment to the parent must be defined as carbon number 1; we number from there; one, two, three, four; this would be a butyl group.2459

But it is just not a butyl group; it has a 2-methyl; it would be called 2-methylbutyl.2472

But it not a 2-methylbutyl because we also have this oxygen; it is going to be called 2-methylbutoxy; it is a 2-methylbutoxy group.2479

Without this, it would just be a butoxy, but now we have a 2-methylbutoxy.2492

We put that all in parentheses and where is that entire group attached to the parent?--to carbon 5; step by step, we will build up these names.2497

Last case here, we have a triple bond; that is going to define our parent--any functional group that modifies the parent name; so instead of having ethane, now you have ethanol or ethene or ethyne.2509

Anything that modifies the name of the parent--double bond, triple bond, or an OH group; that is going to be your higher priority compared to any other ordinary substituent that you have.2524

This is an alkyne; we are going to name it as such; we will number it from here to give the lowest number possible; a four carbon alkyne is called butyne; this is 1-butyne.2534

What do we have attached here at carbon 3?--if this oxygen weren't here, we would call this cyclopentane group, we would call it a cyclopentyl group, right?2546

If it was just five straight chain carbon, we would call it pentyl; now that is called cyclopentyl.2557

With the oxygen, we call it cyclopentoxy... cyclopentoxy; where is this cyclopentoxy?--carbon 3; 3-cyclopentoxy-1-butyne.2563

If we have a nitrogen containing compound, we call those amines; as usual, we are going to find our parent chain that contains the nitrogen.2582

We are going to drop the ?e at the end of the name; we are going to add a new suffix; we are going to add the word -amine as our suffix.2592

It is going to be named as an alkanamine, ethanamine, propanamine, butanamine, so on.2598

It is possible for a nitrogen to have more than one alkyl group; one of those alkyl groups is going to be the parent; the other alkyl groups would be described as substituents.2605

Because they are attached to the nitrogen rather than a carbon chain, we don't give the number of the carbon; we just list a capital N to indicate where it is being substituted.2615

Again, we will find some common names; if it is a simple alkyl group, we will just call it an alkyl amine; we will see some examples of that.2626

We will also see some examples where maybe it is not the highest priority functional group.2634

For example, this amine has four carbons and a straight chain; it would just be called butyl amine or N-butylamine; that would be a common name for that.2639

But its IUPAC would be... longest carbon chain; one, two, three, four; it is a butane derivative; at carbon 1, we have an amino group, we have a nitrogen group; this is called 1-butanamine.2648

We've dropped the -e of butane and we've replaced it with the word ?amine; 1-butanamine.2665

This next one, we have two alkyl groups; one of them is going to be the parent; we will pick the longer one; this is our parent.2674

One, two, three to give the nitrogen the lowest possible number; this is propanamine; this is 1-propanamine.2681

But it is not just propanamine because it has on the nitrogen, it has an ethyl group attached; the way we are going to describe that is with a letter N; N-ethyl-1-propanamine.2691

Just like a number refers to one of the carbons in the carbon chain, a capital letter N, it is italicized, refers to the nitrogen in the compound as the location of the substituent.2703

When an NH₂ is on a benzene ring, we call that molecule analine; we could use that as a parent name; you might come across that name.2716

This NH₃ all by itself was called ammonia; that is not really an organic molecule; it has no carbons in there; but we will see ammonia a lot; you should be familiar with that name.2726

Let's see a few more examples; this is another one that has a very simple common name; how would you describe the alkyl group attached to the nitrogen in this case?2736

It is four carbons arranged, attached to the middle carbon; this is the t-butyl group; we could just call this t-butyl amine as a common name; t-butyl amine.2745

But its IUPAC name, we would have to follow the rules--find our longest carbon chain bearing the nitrogen.2758

That is right there; it is a three carbon chain; one, two, three; this would actually be propanamine.2766

What else does it have attached?--on carbon 2, it has a methyl group; we could call this 2-methyl; 2-methylpropanamine.2775

If we have an OH and an NH₂, we have to decide which one is the higher priority because we can only have one suffix; we can't have an ?ol and an ?amine suffix.2787

The rule is that OH is the higher priority; we would have the same carbon chain in both cases; but in this case, now we are going to name it as an alcohol.2798

We want to give the OH the lowest possible number; so we will number from this direction; one, two, three, four, five, six.2815

This is a six carbon alcohol; we call hexanol; it is a 3-hexanol; remember the ?ol ending tells us there is an OH in the molecule.2822

Now we just simply name the NH₂ group as a substituent, as a group hanging off; just like we have a methyl or a phenyl or a chloro.2835

What we call an NH₂ group is an amino group; we have a 5-amino-3-hexanol; amino just like methyl or ethyl or propyl or bromo or chloro.2842

How about this one?--it looks like we can use that analine as the parent; analine; how is this different from analine itself?2859

It has a methyl group on the nitrogen and a methyl group on the nitrogen; as usual, we combine the common substituents all together.2872

Where are they?--it is a dimethyl, but they are both on nitrogen; we are going to call this N,N-dimethyl; N,N-dimethylanaline; that means each methyl group is on the nitrogen.2882

Here is an example; now we have an ether and an alcohol and a nitrogen; how do we handle this?--thus far, our highest priority group is the oxygen, the OH alcohol.2898

The longest... the highest priority group is the one containing... the parent chain is the one containing the OH; we give the OH the lowest possible number.2910

Everyone else just gets whatever number they end up with; this is actually a propanol; 1-propanol derivative; what do we have attached to it?2920

This is a one, two, three carbon chain; we would call that a propyl; but with the oxygen, we call it a propoxy.2933

Here, if it was just a nitrogen, we would call that an amino group; but it has something else attached to it; what is attached to it?2942

It has a phenyl attached to it; just like IUPAC, this is not... we just do a little IUPAC here; instead of just amino, it is a phenylamino.2950

We don't have to locate the position of it because it is just one atom; it has to be attached to the nitrogen.2960

That would come first alphabetically; we will list that first; 2-phenylamino and then 3-propoxy-1-propanol.2969

A little bit more about amines; we could describe an amine as alkyl or aryl depending on the type of carbon group that is attached.2987

If you have a benzene ring attached, we would call it an arylamine; otherwise, it is an alkylamine.2995

We can also describe the amine as being primary, secondary, tertiary, or quaternary; we define it by describing how many carbon groups are attached to the amines.2999

A primary amine, which we designate with this 1° sign, that means primary, means we have just one R group; then it is an NH₂.3011

Remember nitrogen likes to have three bonds and a lone pair to be neutral.3019

Because this has just one alkyl group, it is described as a primary amine; this would be methylamine or methanamine would be the IUPAC.3023

But if we had two alkyl groups attached, like two methyl groups here, we describe it as a secondary; it is just an NH group.3032

Here we see our two alkyl groups; we would call this diethylamine as the simplest name; here is the IUPAC; you can check that; N-methylmethanamine would be its IUPAC name.3041

Tertiary is what we have when we have three alkyl groups or aryl groups, three groups attached to the nitrogen.3052

This is called triethylamine--would be a common name for this; that is usually how we call it because look how big and awful the IUPAC name is; that is called a tertiary amine.3060

It is even possible to have four bonds to nitrogen; but any nitrogen with four bonds is now going to be a charged nitrogen; this is called a salt.3070

It is called a quaternary ammonium salt; this is called tetramethylammonium iodide; ammonium means we have an N⁺.3082

So it is possible to have even four groups on a nitrogen; but that is going to be an ionic compound.3090

Let's move into compounds that have carbonyls, C-O double bond; the carbonyl is what we call a C-O double bond; there are many functional groups that contain carbonyls.3099

The first one we will talk about is an aldehyde; an aldehyde has the formula here, RCHO; we have a carbon chain on one side and a hydrogen on the other; that is described as an aldehyde.3111

When we have an aldehyde, we are going to find the longest carbon chain that starts at the carbonyl; because there is a hydrogen here, the carbonyl is necessarily at the end of a carbon chain.3127

We start from here and we count our longest carbon chain; the carbonyl carbon is always carbon number 1; we don't say that it is... we don't list it as carbon 1; that is the definition of an aldehyde.3138

What we are going to do is we are going to drop the -e of the alkane name and we are going to add the suffix ?al; it is going to be called an alkanal.3151

The ?AL ending means we have an aldehyde; notice how close that is to an -ol ending we saw for the alcohol.3161

It is very important to have neat penmanship when you are doing these nomenclature problems because the difference of a single letter can mean a right or wrong answer or a totally different structure.3167

As I mentioned, no number is given to indicate where the carbonyl is.3178

Our simplest carbonyl is right here, simplest aldehyde actually; it has a hydrogen on both sides; that is the simplest aldehyde; he is called formaldehyde.3183

If you have ever worked in a biology lab, you are familiar with formaldehyde because this is used as a preservative for dead tissues if you ever dissected a frog or something.3192

That smell that is associated with that is the formaldehyde coming from that preservative solution.3201

This is the simplest case, just a single carbon; that means it is a methane derivative; what do we call this?--we drop the ?e from methane and we add the letters ?al; this is called methanal.3208

Methanal means I have an aldehyde; but almost always this is called formaldehyde instead; it is such a common name.3221

This one where we have the next simplest aldehyde--has just a methyl group on one side; he is known as acetaldehyde; we are going to see this acet common name pop up again and again and again.3228

This acet group or the Ac group represents a carbonyl and a methyl group attached; a COCH₃, a carbonyl with a methyl group attached.3240

Because this is the aldehyde derived from this acetyl group, we call this acetaldehyde; we are going to see this name pop up again and again.3252

But that is its common name; what would its IUPAC name be?--longest carbon chain; we have two carbons; one, two; instead of ethane, we have ethanal.3260

Notice there is no number; we don't say 1-ethanal; that is impossible; it is just called ethanal because the carbonyl has to be a carbon number 1.3271

Here is a more complicated molecule; here is our parent; we must number this way; one, two, three, four; this is a butanol.3281

I have already shown that the carbonyl is the higher priority because that is the fact; the prioritization of functional groups is based on oxidation state.3292

A carbon with two bonds to oxygen is going to be a higher than one with one bond to oxygen; any carbonyl is going to beat out an oxygen, be a higher priority.3301

So we are no longer going to name this molecule as an alcohol; we are going to name this as an aldehyde; now we have to deal with this OH group simply as a substituent.3312

What are we going to call it?--we are going to call it a hydroxy group; we are going to call it a hydroxy group.3322

At carbon 4, we have a hydroxy; this is called 4-hydroxybutanol; notice it is not hydroxyl; there is no -l there; it is just hydroxy.3329

This is benzaldehyde; the aldehyde that is derived from benzene; it is called benzaldehyde; what would its IUPAC be?--let's see if we can come up with that.3341

What is our longest carbon chain containing the carbonyl?--there it is, just one carbon; this is actually a methanal derivative.3351

What does it have attached?--it has a phenyl group; you could call this phenylmethanal.3359

We wouldn't find it named that way very often; but it is important to know both the common names and the IUPAC names.3368

A lot of times, if you go to a chemical supplier catalog and you are looking it up, sometimes it is just as likely to be listed in its IUPAC name as its common name.3372

So it is really important to go back and forth; a lot of times, you pick up a reagent bottle in the lab, and it might have the common name rather than the IUPAC name.3383

That is why they are stressed so often; it is a short list of common names; you do want to be familiar with them so that you can communicate properly.3391

How about this last one?--this is carbon 1; it has to be part of our parent chain; this is where our parent chain starts.3401

We will go like this for our longest carbon chain; we also want to include that double bond; one, two, three, four, five.3409

Let's see, it started out as pentane; the carbonyl at carbon 1, the aldehyde makes it pentanal; the double bond makes it pentenal.3418

We have at carbon 2, we have pentene; then ?al at the ending; remember there is no number for the aldehyde.3432

This number 2 must be referring to the location of that double bond; there is nothing else for it to mean; so 2-pentenal.3441

What else do we have?--we have a methyl group at 3 so 3-methyl; 3-methyl-2-pentenal; anything else for this problem?3448

How about stereochemistry?--let's take a close look at that double bond; is there more than one way to draw this?3460

If I had this carbonyl down in this position, would that be the same molecule?--that would be a unique molecule.3467

We have to show only this stereoisomer was drawn; we have to indicate that stereochemistry as part of our name.3474

Can we use the word cis or trans here to describe this alkene's stereochemistry?--no, because we have more than two groups on the alkene; we have to use the E and Z description.3480

Remember what we do is we separate the two carbons of the alkene; our higher priority group on carbon 3, we have a methyl versus an ethyl; ethyl wins.3492

On carbon 2, we have a carbonyl versus a hydrogen; the carbonyl wins; so our higher priority groups in this case, are they on Zis same side?--nope.3504

They are on opposite sides; opposite sides means E; this is the E stereochemistry.3515

A ketone is another carbonyl containing compound; but in this case, now we have an alkyl group on both sides, a carbon group on both sides of the carbonyl.3525

That distinguishes an aldehyde which is at the end of a carbon chain because it has a hydrogen attached compared to a ketone.3535

What complicates things for the nomenclature of a ketone is you have a carbon chain and that carbonyl can be anywhere along the carbon chain.3543

We are back to the case where we find the longest carbon chain bearing the carbonyl carbon.3551

Then we number it from whichever end is closest to the carbonyl so that the ketone gets the lowest possible number.3556

What is the suffix for a ketone?--we drop the ?e ending and we add ?one; it is called an alkanone; we have to put a number out in front or in the middle to indicate where that carbonyl is.3562

Let's see some examples; the simplest ketone we can have is acetone; the common name is acetone; where does the name acetone come from?3577

Remember that acet, acetyl group we had?--the carbonyl with the CH₃?--if we made that a ketone, the simplest way to make it a ketone is to add another methyl.3587

That is the ketone of the acetyl; we call it acetone; acetone, of course, very commonly used solvent in organic chemistry.3597

We use that in the lab a lot; sometimes for washing glassware, dissolving organic compounds; awesome solvent.3604

Nail polish remover, most nail polish removers are acetone based to dissolve the organic nail polish.3610

It is also very good for dissolving organic inks and permanent inks; you can use acetone; you can use your nail polish remover to dissolve paints and varnishes and all sorts of things like that.3619

So it is a great organic solvent for dissolving organic things; and it is an example of a ketone because we have a carbon chain on either side of the carbonyl.3629

What would its IUPAC name be?--we have a three carbon chain; one, two, three; it is a propane derivative; we are going to call this propanone.3638

Actually, you don't even need to put a number because there is only one propanone you can have; it must be on carbon 2.3648

But we can put that in there just to be safe; it is 2-propanone; ?o-n-e tells the world we have a carbonyl at the number given.3653

How about this next one?--where is our longest carbon chain containing the carbonyl?--let's go this way, number it from the end closest to the carbonyl.3664

We will number this way; one, two, three, four, five; this is a pentane derivative; this is called pentanone; it is going to be 2-pentanone... 2-pentanone.3676

What else does it have attached?--it has a 3-methyl and a 3-ethyl; sometimes students get confused; when they see them at the same position, they try and group them together somehow in the name.3691

But it doesn't matter if they are at the same carbon or different carbons; we list all our substituents as usual; we alphabetize them and we put them out in front.3702

Ethyl comes first; we have a 3-ethyl; methyl comes next; we have a 3-methyl; very simple; no need to panic if they are attached to the same carbon.3709

What if we have a ring here in a double bond?--how do we incorporate all this?--again, anytime we have a carbonyl in a ring, that carbon must be carbon number 1.3723

Because we are going to name it as a ketone; now we will number in this case in a clockwise direction so that the double bond also gets the lowest possible number.3731

Let's see, six carbons in a ring is called cyclohexane; with the double bond, we call it cyclohexene; with the carbonyl ketone, we call it cyclohexenone; this is cyclohexenone.3742

We have a 2-cyclohexene-1-one; 2-cyclohexene, the 2 refers to the double bond; the 1 refers to the carbonyl.3757

Of course, we can break it up completely and put the 2 right before the ?ene and the 1 right before the ?one; you will see that pretty regularly so you should be able to work with either of those.3772

Remember, we don't have to say that this is cis double bond; it has to be cis in a six-membered ring or a five-membered ring.3785

It is when we get to eight or higher that we have the possibility of having cis or trans.3792

This is another common ketone; it is nice to know the name for it; it is called benzophenone when we have a benzene ring and a phenyl group; benzophenone is the common name.3800

How about the IUPAC name?--how about the IUPAC?--we have a one carbon ketone; that is tough to do; that would be the IUPAC; this is a methanone derivative.3808

What do we have?--we have two phenyl groups; we would call this diphenylmethanone; very strange name; IUPAC names end up that way sometimes.3819

How about this last one?--what if we have two ketones?--just like we can have a diol or a diene, we are going to call this a dione.3834

Here is our longest carbon chain; we number it to give the carbonyl the lowest possible number; run into the first carbonyl; we want the lowest possible number.3845

Seven carbons is a heptane; one carbonyl would make it heptanone; this is going to be 2,4-heptanedione.3859

Just like we stuck that ?e back in there when we did a diol just so it is easier to read, we do the same thing anytime there is a di- or tri- or tetra- prefix we have to put in there.3872

So 2,4-heptanedione; what is this group attached to carbon 6 here; what are we going to call that?3882

Without the oxygen, we would just call this a phenyl group; with the oxygen, we will call it a phenoxy; at carbon 6, we have a phenoxy.3889

If we have a benzene ring, we would name the compound with benzene as the parent; let's take a look at some other aromatic compounds that we might encounter in our nomenclature problems.3904

Benzene is our... again, as I said, would be described as a parent as benzene; but there are several heteroaromatics; these are called heteroaromatic compounds.3918

That means we have aromatic rings with something other than carbon, a heteroatom--nitrogen, oxygen, sulfur, something like that.3932

These are also aromatic compounds; and these are very common names that you should be familiar with.3940

Benzene with a nitrogen replacing one of the carbons is called pyridine; this is called pyrrole, furan, and thiophene; those are real common ones that are good to know.3946

When we go to number a benzene, any of these carbons can be defined as number 1; you make that choice; but in a heteroaromatic, the heteroatom is defined as position number 1.3955

This would be 1; then you number in whatever direction you want; one, two, three, four, five, six.3967

A 2-methylpyridine means that the methyl group is attached on the carbon right next to the nitrogen; same with pyrrole oxygen; the heteroatom is always position number 1.3971

We can have some fused aromatics; it is called fused when some aromatic rings share sides; this guy is called quinoline, for example; two benzene rings attached to another is called naphthalene.3984

Naphthalene is used for moth repellants; moth balls have the same kind of smell that naphthalene does; very aromatic actually; which is where the name came from.3998

Anthracene, when you have three together, and so on; there is lots of them; just showing a few examples here; but when you have a fused aromatic, let me show you the numbering.4010

We start with one of the carbons next to the point of fusion; then we go around one ring--one, two, three, four; then we jump to the next ring--five, six, seven, eight.4019

We do not number... we skip the numbers for these because those carbons already have four bonds to carbon; there is no way you can add a substituent to those positions.4028

That is interesting; a 1,5-dimethylnaphthalene means that we have them in this position and this position.4039

When we have two benzene rings directly attached to each other, that is called a biphenyl; that is a common name--is biphenyl.4048

You may have heard of PCBs; that stands for polychlorinated biphenyls; these were used as insecticides and such.4056

They have all sorts of long lasting environmental impact so those have all been phased out; so PCBs are an important chemical that we are trying to mitigate in the environment.4068

How about the IUPAC for a biphenyl?--what would you call that?--one of these benzene rings would have to be the parent; you just pick one; that is our parent so this is a benzene derivative.4080

That is our parent; what does that benzene have attached to it?--it has a phenyl group; phenylbenzene would be the IUPAC name; phenylbenzene is another way to say biphenyl.4092

It is also nice to be familiar with these names of aromatic compounds because a lot of times the common names for other compounds are derived from the aromatic name.4108

For example, this molecule looks a lot like furan; it has the same skeleton as furan except we've gotten rid of both of these double bonds.4120

So this molecule is described... it has a common name; it is called tetrahydrofuran; because it is the same thing as furan, but we have added four hydrogens to it.4129

This is called tetrahydrofuran; it is abbreviated THF for short; that is a very common solvent that is used in organic chemistry.4140

If you have substituents on the benzene ring, we can number the ring just as usual--one, two, three, four, five, six, and describe it that way.4150

But if you have just two groups on a benzene ring, there is only three possible arrangements for those two groups; so we have common names to describe those possible relationships.4157

If we have two groups that are 1,2 to each other, meaning they are on adjacent positions, we describe that as being ortho di-substituted.4167

We either can put the word ortho in italics out in front or we could just use the letter o- will represent ortho; that describes where the two groups are attached.4176

When they are 1,3, meaning they skip over one carbon, we call that the meta arrangement; when they are 1,4, they are opposite to each other, they are called para.4186

Those are the only three possibilities; if I move the substituent over here now to the other side, this is meta again; and if I move if up here, it is ortho again.4195

So ortho and meta and para are the only three possibilities.4203

When we start getting into aromatic chemistry and learning about the reactions of benzene and benzene derivatives, we are going to be using the terms ortho, meta, para again and again.4205

You are going to eventually become very familiar with these; they can be used to very easily name aromatic compounds if we could do some common names.4217

For example, we have a bromo and iodo here; they are 1,3 to each other; they are meta; we could just describe this as meta-bromoiodobenzene.4226

Benzene is the parent; I have a bromine and an iodine; they are meta to one another; it is a flat molecule; it doesn't matter where you put the bromine, where you put the iodine.4239

As long as you put them 1,3 to each other, you are going to end up with the same compound every time; so it is really easy nomenclature.4248

If you want to number it and do it that way, now you have to be concerned with who gets carbon 1 and so on; for this, we are going to do it just like we did for cycloalkane.4253

We are going to pick the one, the substituent with the lowest... that comes first alphabetically, and we will give that to be carbon 1.4264

The bromo comes first; he would be carbon 1; then we number to give the iodine also the lowest number; we would call this 1-bromo-3-iodobenzene; it is a lot more complicated than just calling it meta.4271

We call it benzoic acid; we will see this... we will talk about carboxylic acids in a moment, on how to name those; but he is called benzoic acid; so this could be called ortho-hydroxybenzoic acid.4290

Ortho describe the relationship; so ortho, meta, and para are good to do that; or you could call it 2-hydroxy as another possibility instead of ortho.4309

But then when you have more than two groups, you can't use the words ortho, meta, and para anymore because those words have no meaning.4324

Here you could say that the two methyl groups are meta to one another; you could still use it as an adjective to describe the relationship of two groups.4332

But this molecule can no longer be described as an ortho, meta, or para molecule because there is more than two groups.4340

In this case, we are going to go back to our nomenclature rules where we find whoever comes first alphabetically, gets the lowest number.4346

We have an ethyl versus a methyl; this is number 1; then we number either clockwise or counterclockwise depending on which will give the lowest number to the next substituent.4353

We will number this way; one, two, three, four, five, six; our parent is benzene; our parent is benzene and what substituents do we have?4364

We have a 1-ethyl; how do we handle our 2-methyl and our 4-methyl?--we group them together and we call it 2,4-dimethyl; so naming a benzene is pretty straightforward.4374

There is never any stereochemistry to worry about because it is a planar molecule; every carbon can only have one substituent on there so that simplifies things.4389

But when we get into the heteroaromatic compounds, then that nomenclature can expand our vocabulary a little bit.4399

There is also a lot of common names that exist for simple compounds and simple mono-substituted benzenes; these are very useful to be familiar with.4410

In fact, you may even be required to learn them; that is quite likely.4422

For example, methylbenzene, when we just have a methyl group on a benzene ring, that is known as toluene.4426

Toluene is a very nice solvent that we use for organic chemistry; it is preferred over benzene because it is not carcinogenic; so that has some uses as well in the lab; that is called toluene.4432

It is called phenol when you have an OH on a benzene ring; it is a very special type of alcohol when you have an OH attached to a benzene ring; it is called phenol.4447

Notice the ?ol ending is just like we have for an alcohol; but it is not called benzol; it is called phenol.4457

I see I have a little typo here, sorry... this is called anisole; we will copy and paste here... it is called anisole when we have a methoxy group here instead of a methyl; it is called anisole.4465

When we have a nitrogen, this is called aniline; when we have two methyl groups, those compounds are known as xylenes.4477

Notice that this bond is pointing to the middle of the ring; that is because there is three possible places to put that second methyl; we could put it ortho or meta or para to the first methyl.4486

So there is three isomers of xylene that exist; ortho-xylene, meta-xylene, and para-xylene; together we call these the xylenes if maybe you had a mixture of those dimethyl benzenes.4498

Finally, it is called a cresol when you have an OH and a methyl; so some of these very simply substituted benzene rings have common names.4511

You are guaranteed to encounter them so being familiar with them is really going to pay off.4521

For example, this one has a methyl and an OH; they are para to each other; so this molecule can be called para-cresol.4527

Or it could be called para-methylphenol; para- or maybe 4-methylphenol; or it could even be called hydroxymethylbenzene; all sort of names you can come up with for aromatic compounds.4536

A lot of times, we get to a situation where there are more than one acceptable names; you definitely want to check with your instructor to see what their expectations are.4555

This is an interesting aromatic compound; it is a toluene derivative; see the word toluene in here?--it is called trinitrotoluene; here is the toluene; that means methylbenzene.4565

It is a derivative of that because it has these four nitro groups on it; guess what this is called?--trinitrotoluene; this is called TNT.4576

So this is the structure of dynamite; that name, when you explore that name, it comes from the common name of this aromatic derivative; very explosive.4585

Let's take a look at carboxylic acid; this is another carbonyl containing compound; a carboxylic acid has this formula here.4597

We have a carbonyl and an OH group attached; this is no longer now an alcohol; it is no longer a ketone or an aldehyde.4607

This arrangement of atoms is combined together, taken as one, as one functional group, called a carboxylic acid; it will be named as a carboxylic acid.4618

It must be at the end of a carbon chain because it has a... the oxygen stops the carbon chain; once again, like the aldehyde, the carboxylic acid defines the beginning of the carbon chain.4629

We number from that point onward to decide how long our parent chain is; but we never have to designate that the carboxylic acid group is a carbon 1 because that is the definition; it must be.4642

What we are going to do is we are going to drop the ?e ending of our alkane, and we are going to add two words; we are going to make the first word ?oic as our suffix.4655

Then we are going to do a space and then the word acid; so we are going to have an alkanoic acid; that tells us we have a carboxylic acid.4663

Again, a few common names here; our simplest acid with just one carbon is known as formic acid; this has a real interesting history for this name.4672

This is the acid that can be extracted and isolated from ants; if you take some ants and smash them up and extract the organic or acidic component, you will be able to isolate formic acid.4682

The Latin word for ant is formica; this was called formic acid since it is the acid derived from ants.4694

Again, very commonly called, typically called formic acid; but its IUPAC would be derived from the fact that it is just one carbon; it is a methane derivative.4704

But instead, we call it... we drop the ?e ending of methane and we add the suffix ?oic; then we make a space; then we put the word acid; so this is called methanoic acid.4714

Methanoic acid means I have a one carbon carboxylic acid; I have one carbon and, on that carbon, I put a carbonyl and an OH; that is what makes it a carboxylic acid.4728

This guy is called acetic acid; why do we call it acetic acid?--there is our acetyl group, our carbonyl with a CH₃; when we make it a carboxylic acid, we will call that acetic acid.4739

Acetic acid is actually the acidic component of vinegar; that is what makes vinegar smell and taste that characteristic smell; it has that bite, that acidic bite.4749

Most often, we call it acetic acid; we abbreviate it AcOH by the way; a lot of times you will see that abbreviation, the Ac group, representing the carbonyl with the CH₃.4762

What would its IUPAC name be?--what is its IUPAC name?--here we have a one, two carbon chain; it is an ethane derivative; we are going to call this ethanoic acid; two words, ethanoic acid.4773

How about a more complex carboxylic acid; here is our parent; we have to start at the carbon bearing the carbonyl.4788

Both of these functional groups... both of those atoms are going to be incorporated into our parent name; one, two, three, four, five; five carbon carboxylic acid is called pentanoic acid.4797

I do not need to say 1-pentanoic acid; there is no such thing; it has to be at carbon 1; what else do I have on carbon 4?4812

Now we take our substituents, we alphabetize them, we put them out in front as usual; we have a 4-methylpentanoic acid.4819

Benzoic acid is what we call the carboxylic acid with a benzene ring attached to it; benzoic acid; that is good to know.4829

We also need to know, now that we have learned about carboxylic acids... remember the priority of functional groups depends on oxidation state.4837

A carboxylic acid is the most oxidized we can have for a chain; so that is going to be our highest priority.4845

That means we are going to have to find a name for any other carbonyl that is in the structure; an alcohol group is also going to be named as a hydroxy.4855

In this example, we have three functional groups; we have an alcohol and we have the ketone and we have a carboxylic acid; all three of those functional groups exist.4865

Which is the one that is going to define the IUPAC name?--the highest priority is the carboxylic acid.4873

This is our parent chain; we are going to number to give the carboxylic acid carbon 1; so this actually incorporates the carboxylic acid; if you want to circle that, that is even more clear.4881

This is butanoic acid; no numbering there to put in our name; this is butanoic acid; we know that the alcohol group is the... the OH group is going to be called hydroxy.4894

What is a carbonyl going to be called?--it is not a keto group anymore... because it is not a ketone anymore; it is going to be called an oxo group; oxo means you have a carbonyl; not oxy; oxo.4907

Who comes first?--hydroxy comes first; we will list that first; 4-hydroxy-3-oxo-; and this is all one word, 3-oxo-butanoic acid.4919

Oxo is what we will call a carbonyl; hydroxy is what we call an OH; both of those are lower priority than the carboxylic acid.4932

Remember you can only pick one suffix; every other group then becomes named as a substituent listed out in front.4940

Now that we know how to name a carboxylic acid, let's take a look at some related functional groups.4950

These are called carboxylic acid derivatives because they can all be derived from a carboxylic acid; they are all related to a carboxylic acid.4954

We can have a... what we are doing is we are varying the group attached to the carbonyl; a carboxylic acid had an OH; and we are varying the group.4963

What all these have in common is that each of these groups has lone pairs; a halogen, remember X represents a halide.4975

A halogen has three lone pairs; oxygen has two; oxygen has two; nitrogen has one; you can see that the general structure for these carboxylic acid derivatives looks like this.4984

It has something attached to the carbonyl with a lone pair; we are going to describe this as a leaving group; this is actually going to define the reactivity of carboxylic acid derivatives.4996

We are going to see that being involved in reaction mechanisms as a leaving group; we will get to that down the road.5009

The nitrile doesn't look a lot like a carboxylic acid; but it is related just like this.5016

All of these have a carbon with three bonds to heteroatoms--an oxygen, and an oxygen, and something else with a lone pair.5023

This also has three bonds to a heteroatom, three bonds to nitrogen; so even though he looks a little different, he is also related; this is called a nitrile.5030

It is called an amide when you have a nitrogen attached to the carbonyl; it is called an ester when you have an OR group; so it is no longer an ether.5040

An ether means I have R... alkyl, and then an oxygen, and then an alkyl; that makes it an ether; when one of those groups is a carbonyl, we call it an ester.5048

When both groups on either side of the oxygen are carbonyls, we call that an anhydride; if we have a halogen attached to the carbonyl, we call it an acid halide.5058

One by one, we will go through the nomenclature for these; but I just wanted to put it in context, showing you that each of these is related to the parent carboxylic acid.5067

Because if you know how to name the parent carboxylic acid to which these are all related, then it is going to be a little easier to name the particular derivative we are looking at.5078

We will start with an acid halide; what we will do is we will find the longest carbon chain that starts at the carbonyl carbon.5090

We have to start at the carbonyl carbon; it is always carbon number 1; so we don't even mention that, just like a carboxylic acid.5097

What we do is we drop the ?e and we add the letters ?oyl; we are going to get an alkanoyl halide; then we are going to list the halide, making it an acid halide.5104

For example, again coming back to our common names, a common name for this molecule would just be called acetyl chloride; this is the acid chloride derived from acetic acid; we call that acetyl chloride.5118

What would its IUAPC name be?--we have a two carbon chain; one, two; it is an ethane derivative; but we are going to drop the ?e and add ?oyl; ethanoyl.5131

We make a space; this is another two word name; and we list whatever halogen happens to be here; it is most often chlorides that we deal with.5144

You will see that nine times out of ten; but it is possible to have other halides as well; this is called ethanoyl chloride.5151

Again, pay very close attention to these details; if you drop the -o, that name doesn't exist.5157

If you drop the -y, then you are talking about an alcohol and you've made a mistake; so be very careful; -o-y-l as our ending for an acid chloride; ethanoyl chloride.5163

How about this one?--what is our longest carbon chain?--we can include the acid chloride if you want; there is our longest carbon chain.5174

Be very careful, when you have a cyclic substituent, that you don't include the carbon of the ring as part of your carbon chain; you can't count it for both.5183

Here it is the group that is attached to the carbon chain; this is a one, two, three, four carbon chain.5192

What is a four carbon acid chloride called?--it is called butanoyl; butanoyl, space, chloride; butanoyl chloride.5201

What is attached to carbon 4?--it would be called cyclopropane if that was the parent; but as a substituent, we call it a cyclopropyl group; cyclopropyl; 4-cyclopropyl... 4-cyclopropylbutanoyl chloride.5213

How about this one?--what is our parent carboxylic acid we have?--if this were a carboxylic acid, if this were an OH, we would call that benzoic acid.5235

We are going to call this benzoyl bromide; that is our parent; kind of related to benzoic acid; we call it benzoyl bromide.5246

What do we have attached?--we have another bromo substituent; it is in the meta relationship; we could just call this meta... I'm sorry, 3-bromobenzoyl.5262

Or we could call this meta-bromobenzoyl bromide; those would both be good names for this compound.5275

Benzoyl bromide means I have something that looks like benzoic acid--a benzene with a carboxylic acid; but it is a bromine there instead of an OH.5281

An anhydride name is also very closely related to the parent acid to which it is related; let's just take a look at the structure of the anhydride.5293

If you think of the anhydride structure, it kind of looks like we have two acid pieces that have come together.5302

If you think of these two acids, what would they have to lose to result in the structure shown?--it looks like we've lost the OH on one and the H on the other; so we lost H₂O.5306

If we lose H₂O, these two carboxylic acid groups can come together and form the structure, the product, shown; that is why it is called an anhydride--you've lost water.5323

In the simplest case, where these two alkyl groups are the same, then we simply name it as the parent acid; but instead of calling it an alkanoic acid, we call it an alkanoic anhydride.5336

For example, this came from acetic acid; this is related to acetic acid; we could call it just acetic anhydride as its common name; this is acetic anhydride.5347

The abbreviation for that is Ac₂O; it has two Ac groups, acetyl groups, attached to the middle oxygen; but what is its IUPAC name?5362

For the IUPAC name, let's take a look at just one half and name that acid; that acid would be a two carbon acid; it is an ethane derivative; this would be ethanoic acid.5372

Ethanoic acid, so now we call this ethanoic anhydride; we just replace the word acid with anhydride.5385

What if it is not a symmetrical anhydride?--we call those mixed anhydrides, meaning it came from two different acids if you will; then all we do is list both acid groups before the word.5395

What carboxylic acid did this come from?--one, two, three; this was a propanoic acid; and over here, this came from one, two, three, four; this came from butanoic acid.5408

When we brought those two acids together, if we think about that as a way to come up with the IUPAC name, we just list them alphabetically; this is butanoic propanoic anhydride.5424

That is so simple; it seems like that would be a common name but that is actually how you do the IUPAC name; you just list the two halves to the anhydride.5442

If you had a diacid like this... again, there are common names associated with most of these diacids; oxalic, molaic, succinic, glutamic, and so on.5451

These are... you might come across these common names; it is going to be useful in this case; this is called succinic acid.5465

Let's try and do the IUPAC for this one just to see if we could do that; it is a four carbon chain; one, two, three, four; one, two, three, four; it is a butane derivative.5472

If we had just one carboxylic acid, we would call it butanoic acid; because we have two, we call this butanedioic acid.5484

Remember we add that -e back in so we can fit the d-; butanedioic acid; remember ?oic acid is our suffix; just like we would have diol or dione, we could have dioic acid.5498

If we take succinic acid and lose water from this structure, what can happen is the two carboxylic acid groups can come together to form a cyclic anhydride.5512

In fact, we are going to be seeing the mechanism of this eventually; what we will get is a five atom ring that looks like this.5522

That is an anhydride structure; you have the oxygen with a carbonyl on both sides; this is definitely anhydride.5532

The way we describe this anhydride is by referring to the parent acid it came from; this is called succinic anhydride; succinic anhydride.5539

Believe me, you don't want to know the IUPAC name for this; this is really how most of us refer to it--is just by its common name.5554

Some of these cyclic anhydrides you will see are named... their name comes from the common name of the parent diacid.5561

I think esters are a little tricky to name because an ester has two R groups; it has the R group that is attached to the carbonyl side; and it has the R group that is attached to the oxygen side.5572

It is possible to mix those up when you are first learning; but let's see how we can keep them straight.5587

I think the way to do that is to immediately take a look at an ester structure and immediately break it down to--here is the parent acid to which this ester is related.5594

This looks like the carboxylic acid group; this is the parent chain; this is the parent right here; and this is just an additional alkyl group that added on to make it an ester rather than a carboxylic acid.5605

What we are going to do is we are going to drop the suffix ?oic acid and instead we are going to use the suffix ?oate to tell everyone that it is an ester instead.5621

What we are going to do then is we are going to list in front, we are going to list the alkyl group that makes it an ester.5632

Ultimately, our name is going to be an alkyl, space, alkanoate; the alkyl group is this part that is attached to the oxygen; the alkanoate is our parent just like the alkanoic acid was.5640

A lot of words; let's just look at some examples and I think it will make a lot more sense.5653

For example, this is acetic acid; we call that acetic acid; its IUPAC is ethanoic acid; ethanoic acid is related to this ester because we still have the components of ethanoic acid.5658

We still have the two carbons and the carbonyl with the oxygen attached; but it is now an ester because there is an R group here; there is an alkyl group instead of a hydrogen.5675

Instead of calling it ethanoic acid, we are going to call it ethanoate; we are going to use the suffix ?oate to indicate that it is an ester.5686

There are a lot of ethanoate esters you can have; all sorts of different esters you can have because this alkyl group can vary.5697

Which ester do we have in this case?--we have the methyl ester; we just list the word methyl out in front; this is methyl ethanoate.5704

Its common name for an ester would be acetate, for this acetyl group as an ester; we would call this methyl acetate; that is a very good common name to know as well.5715

Let's try another example; this is an ester because we have a carbonyl with an OR group attached.5726

How do we name it?--first we really want to identify the parent acid; here is the carboxylic acid that is related to the ester of which it is a derivative.5735

How would you name that acid?-it is a three carbon acid; one, two, three; it is a propane derivative; you would call it propanoic acid.5747

We are going to name this propane ester, we are going to call it propanoate; we are going to call it propanoate; drop the -e and add ?oate; so it is propanoate.5757

Which ester is it?--what do we have over here?--this is an ethyl group making it an ester; we call this ethyl, space, propanoate; esters are named as two words; ethyl propanoate.5770

Let's try another one; this one is a little more complex; here is our parent ester, a parent chain because that came from the carboxylic acid.5786

Remember the carboxylic acid is the highest priority functional group; that must be our parent; we are going to number from there; one, two, three, four, five.5800

It is pentane that we started with originally; but we have a double bond here; so this is actually going to be called 4-pentene... 4-pentene.5811

But it is not pentene; it is an ester; what suffix do we use for an ester?--we drop the ?e and we add ?oate; this is called 4-pentenoate.5823

Remember double bonds and triple bonds, we can always sneak into our name because they affect a different part of the parent name.5836

They just replace this -a with a -e or a ?y; so we can always incorporate those in there.5844

4-pentenoate; the 4 must be referring to the double bond because the ester needs no number; the ester must be on carbon 1; this is good so far.5849

Now we ask what is the alkyl group that is making it an ester?--we come over here; this is a little complicated now.5859

This is a complicated group; we just have to recall that the carbon point of attachment is defined as carbon 1.5868

What is our longest carbon chain?--that is it; it stops right there; this is a methyl group... this is a methyl group.5878

But it is not just methyl; what does it have attached to it?--it has a phenyl group attached to it; we are going to call this phenylmethyl; phenylmethyl, space, 4-pentenoate.5884

Phenyl methyl, I just realized was on the previous slide; I forgot to mention that with the aromatic nomenclature.5900

This group, there is a common name for a benzene ring with an extra carbon; it is called a benzyl group.5908

The carbon next to a benzene ring is described as a benzylic position; this is called a benzyl group.5917

A common name for this might be benzyl 4-pentenoate; that would be the common name; but the IUPAC name is phenylmethyl, space, 4-penteneoate.5922

Once we figure out how to name esters, it turns out we can use that same nomenclature to describe carboxylate salt; it is called a carboxylate when you have an RCO₂^-.5932

RCO₂^-; it is like a carboxylic acid that has a lost a proton; it has been deprotonated; we call that a carboxylate; we use the exact same rules to name this.5945

Again, we look at the parent acid from which it is derived; this would benzoic acid; now we call it a benzoate with the negative charge there; this is called benzoate.5958

In this case, it is not an alkyl group that is making it the benzoate; it is a sodium; we just list the counter ion in front; sodium benzoate.5974

So you could have sodium acetate; you could have... you could have lithium pentenoate here if this was the lithium salt.5983

You will come across those names as well when you are looking at carboxylate salts; so that is good to be familiar with that nomenclature.5995

Amide nomenclature goes as follows; an amide is when you have a carbonly with a nitrogen attached.6005

It is no longer an amine; that carbonyl now makes it an amide; again all the difference that a single letter makes.6013

Once again, this must be carbon 1; we count the carbons from that point forward, find the longest carbon starting from there.6020

What we for our name is we drop the ?e and we add the entire word -amide; so we get an alkanamide as the parent; the suffix is the entire word ?amide.6028

If we have groups attached to the nitrogen, as usual just like we did for the amines, we will identify those as N-substituent.6040

Again let's look at the very simplest example; acetamide is what we call it when we have the acetyl group that is turned into an amide.6049

What would its IUPAC be?--we just have a two carbon chain; that is an ethane derivative; this is an ethane derivative.6058

We drop the ?e of ethane and we add the word ?amide; ethanamide; ethanamide would be the name of this compound.6066

This guy is called N,N-dimethylformamide; let's see if that name makes sense to us; where does formamide come from?--it comes from formic acid.6077

Formic acid was our simplest carboxylic acid; that is the one that came from ants; like formaldehyde.6087

That is where the name formaldehyde comes from--is related to formic acid; that is the aldehyde with this one carbon structure.6096

This is the one carbon amide; we call that formamide; it is N,N-dimethyl because there is two methyls on the nitrogen; that is N,N-dimethyl.6103

Formamide is its common name; that is a good one to know because it is abbreviated DMF; this is a solvent that is used in organic chemistry; so you might see the abbreviation DMF occasionally.6112

How would this name change if we wanted to do IUPAC?--because formamide is not an IUPAC name; what would the IUPAC name be?6125

This is just a one carbon chain; that means it is a methane derivative; we would just call it methanamide; we drop the ?e of methane and add -amide.6134

It would still be the same beginning; it would still be N,N-dimethyl; but it would be N,N-dimethylmethanamide rather than N,N-dimethylformamide.6145

Let's try an example here; we have a lot going on; let's identify the highest priority functional group and let that set which one will be our carbon chain, our parent chain.6156

Right here, this is the carbon that is most important because that has the carbonyl and the nitrogen; that is going to be our parent chain.6170

This is the longest carbon chain from that point on... from that point on; this is one carbon, two, three, four; this is a four carbon chain.6177

What is that going to be called?--it looks like a butanamide; butane derivative; now butanamide; butanamide means that I have an amide at carbon 1; carbonyl plus a nitrogen.6188

What else do we have here?--we have an N-ethyl; a lot of times the N substituent is listed all the way out in front of the molecule before the carbon substituents are sometimes mixed in.6203

It maybe depends on the publisher; this is called an N-ethyl because it is an ethyl group on the nitrogen.6216

What is this group called?--what is that group called?--if you could use common names, there would be a simple name for this; it looks like the isopropyl group with an oxygen.6224

We could call this an isopropoxy; we could call it an isopropoxy but that is not IUPAC; let's figure out an IUPAC name for this substituent.6235

Remember the point of attachment has to be carbon 1; this is a two carbon chain; this is actually an ethyl group.6248

But it has a methyl at carbon 1; it is a 1-methylethyl is how we would call an isopropyl group; but it also has the oxygen here; we are going to call this 1-methylethoxy.6257

It is actually an ethoxy group; here is the ethoxy; but it is a derivative of that because, at the 1 carbon, it has an extra methyl; this is called a 1-methylethoxy.6274

Like I said, usually the end substituent come first; it turns out that is also alphabetically correct; so we are in luck here.6286

This is N... I'm sorry, N-ethyl is listed first; then at position 2, we have this big whole group; -2- and then parentheses to keep it all together; a 1-methylethoxy.6295

Our nomenclature rules are building on one another bit by bit so that we can eventually name some pretty complex molecules.6313

Finally let's take a look at a nitrile; a nitrile is RCN; so we have that C-N triple bond group; that is also a carboxylic acid derivative.6323

It also indicates that the first carbon, the carbon of the nitrile, defines the beginning of the carbon chain; just like the carboxylic acid derivatives.6336

I typically don't bother trying to distinguish who has a higher priority among the carboxylic acid derivatives.6346

Assuming you have just one of those, that is going to be higher priority than any other functional group we saw.6353

But if you want to get into the details of how do they rank amongst each other, you can look that up and have those challenging problems.6359

We are going to find our longest carbon chain; then we are going to not even drop the ?e of our alkane name; we are just going to add the word nitrile.6367

That must be the simplest suffix to remember because you don't even have to drop the ?e; you just stick the word nitrile on the end; that magically turns your carbon chain into a nitrile instead.6377

This is a tricky one to recognize; this molecule's common name is acetonitrile; but you can see that it is the two... just like... remember this was the acetyl group.6391

It is the two carbon derivative that we had all these names for--acetone, acetic anhydride, acetic acid, acetamide, etc; the two carbon nitrile is called acetonitrile.6402

Again, even though it looks quite different from the others, this is a common name; another very common solvent to use in organic chemistry; so you might see acetonitrile around.6415

But what would the IUPAC name be for acetonitrile?--our longest carbon chain is right here; it is just a two carbon chain; that is an ethane derivative; he is called ethanenitrile.6423

That is it; you just add the word nitrile to the end; ethanenitrile; notice that the cyano group is part of the carbon chain; it is part of the carbon chain; that is important here.6435

You might at first glance, at the way this is drawn, you might think that your parent is down here and then you have some kind of cyano group attached.6445

It would be called a cyano group if we had some higher priority functional group here; but we don't; the cyano group is the highest priority functional group.6453

So that is actually part of our parent; our carbon chain has to start right here; from that point, our longest carbon chain goes in either direction because it is symmetrical.6460

But this must be our parent; one, two, three, four, five; this is actually a pentane derivative; we are going to call that pentanenitrile... we are going to call that pentanenitrile.6470

What do we have attached?--we have some methyl groups; and then we have another one of these complex substituents; let's see if we can tackle that; how do we start?6488

We look at the point of attachment to the parent; we define that as carbon number 1; then we number from there; what is the longest carbon chain starting from that point?6496

The longest carbon chain would be one, two, three; it doesn't matter if you number up here or down here; one, two, three; this is actually a propyl group.6506

It is a propyl group; but that does not... it is not just a propyl group; it has a methyl at carbon 1 and a methyl at carbon 2.6514

What are we going to call this?--we are going to call this a 1,2-dimethylpropyl; it is a 1,2-dimethylpropyl.6524

We are going to put that whole big thing in parentheses because it is all one group that is attached to the parent; it is attached to the parent at carbon 2; it is called a 1,2-dimethylpropyl.6537

I listed that last... I listed that second because the other groups we have are methyl groups and methyl comes before methylpropyl.6551

Remember we ignore the di- for alphabetizing; but methyl comes before methylpropyl because methylpropyl is all one word.6559

At 3, we have a methyl; at 4, we have a methyl; we are going to call that a 3,4-dimethyl.6565

Make sure you give yourself plenty of room when you are doing these nomenclature problems because the names can get really big and long.6572

Make sure you draw your letters nice and large and clearly so that there is no mistaking an ?e for an ?a or ?o because, as you can see, that makes all the difference in getting these problems correct.6578

Let's do this last one; this looks like a doozy doesn't it?--we have an aldehyde; we have a ketone; we have an alkene; we have a nitrile; which of these groups wins?6591

Remember it is based on the oxidation number; any carbon with three bonds, two oxygen, or two heteroatoms is going to win; so this is our highest priority functional group.6604

He will be named as a nitrile; all the other groups are just substituents attached to the parent because we can only have one suffix.6615

Let's include that nitrogen in our parent so we make sure that we have already accounted for it; one, two, three, four, five, six, seven; seven carbon chain is heptane.6624

Double bond makes it heptene; we have a 2-heptene... 2-heptene; how do we make this a nitrile?--we just add the word ?nitrile to the end.6643

That means the first carbon of that seven carbon chain is part of a carbon-nitrogen triple bond; we have 2-heptenenitrile.6659

What do we have at carbon 4?--remember we would name it as a ketone if that was the highest priority functional group; then we would use the ?one suffix.6667

But now it is a substituent; he is not called a keto group; that is a really common mistake; instead he is called an oxo group; any carbonyl is called an oxo substituent.6679

We have an oxo at 4 and we have an oxo at 7; again now an aldehyde or a ketone, they are both the same thing, they are just carbonyl substituents.6689

We are going to call this a 4,7-dioxo; just like we would have a dimethyl or a dichloro or a diphenyl; this is called a dioxo; excellent.6700

That accounts for all our functional groups; but there is one last thing that is missing here; is there any stereochemistry that might be relevant?6717

Look at this double bond; how would you describe that stereochemistry?--both of these groups are pointing in the same direction, on the same side.6724

So yes, actually the cis isomer has been shown here; we need to show that; it is okay to just call it cis here because you have only two groups.6731

It is also okay to call it Z; it is never wrong to use the E and E nomenclature; if you want to get used to doing that, then that is a good idea.6739

Z means these two groups are on Zis same side; in fact, in some cases, sometimes you will learn that unless you have two identical groups, they prefer not to use cis but to use Z instead.6750

But if you have two hydrogens, it is quite unambiguous if you call it cis; that is why they accept it as an okay name as well.6763

That wraps it up for all the different functional groups that we are going to learn the nomenclature for; I realize nomenclature is not the most fascinating topic in the world.6774

But just like you have to memorize the alphabet before you can learn how to spell and learn how to put words together, you do need to memorize these nomenclature rules.6782

It is one of the few things in organic chemistry that really you do have to memorize; you do have to know the names; because we need to be able to communicate.6791

If every time you see one of these IUPAC names, it is a huge roadblock for you when you are going to have to spend ten minutes figuring out what it means; that is going to be very costly.6799

So it is worth to maybe put together some flashcards and start to get familiar with these; of course, the more problems you work on, the better you are going to get.6808

And the more it is going to be second nature to you just like the alphabet is now that you have had plenty of time to practice that.6817

Hope to see you again soon; thanks for coming.6824