What I want to do in this video
is talk about a bunch of
molecules or classes of
molecules that can be derived
from carboxylic acid.
And just to show a specific
example I'll show things that
can be derived from
acetic acid.
And just as a review, acetic
acid looks like this.
The common name, as I just said,
is acetic acid, and if
you want to use the systematic
name, you look for the longest
chain, which is right
over there.
There's two carbons.
So we use the eth- prefix, so
it's ethan-, and since this is
a carboxylic acid, it
is ethanoic acid.
Now, the derivatives of acetic
acid, and we can later
generalize this to all
carboxylic acids.
We really just have to change
what's going on in this carbon
chain right here.
It won't have to necessarily
just be two carbons.
It can just keep going.
It could have benzene rings,
whatever, and that would
change the name.
But really, I just want to give
you the gist and the gist
of the naming.
So if we were to replace this
hydroxyl group with an amine,
and in future videos we'll see
how that is done, so let me
just draw the acyl group.
So the acyl group is just
that right over there.
And we're just going to keep
changing what's bonded to the
acyl group right over here.
So if this is bonded to an
amine, so let me draw-- well,
this would be the simplest amine
right over here, which
would be NH2.
This thing right here it's
called an amide, and if we
were to give this its common
name, it would be acetamide.
This particular example
would be acetamide.
And if we wanted the systematic
name for it, it
would be ethanamide.
You have two carbons right there
so it is ethanamide.
Now the natural question is,
all amines won't just be
primary, you might have other
things other than hydrogens
attached to it, other radical
groups, other carbon chains,
so how do you name those?
And so if you had a molecule
that looked like this, and
actually, let me just change
things up a little bit so that
we diverge a little bit
from the ethane route.
So let's say you had three
carbons bonded or part of the
acyl group right there.
And then, we are bonded to a
nitrogen, which is bonded to a
methyl group and then
another hydrogen.
In this case, you start naming
with this methyl group right
here and to show that that
methyl group is attached to
the nitrogen, you call
this N-methyl.
And then you look at the chain
that forms the acyl group, the
carbon chain.
We have one, two, three carbons
so it is propanamide.
If you had another methyl here
you would say N comma
N-dimethyl.
If you had a methyl here and
a propyl group here, you
would've called it
N-methyl-N-propyl-propanamide.
So hopefully that gives
you a sense of amides.
Now, and this is something we've
seen before so it's a
little bit of review, if you
have something that looks like
this, I'll have it attached
to a methyl
group right over here.
We've seen this before.
This is an ester.
And if we have an-- let me
actually make the part that
makes it an ester in blue
to diferentiate it.
We keep substituting what is
attached to the acyl group.
Let me label it.
This right here is called
an acyl group.
That right there is
an acyl group.
So right over here, for the
ester, if we were to give it
its common name, and we've
seen this ester
before, it is acetate.
And if we wanted to give it its
systematic , name you look
at the longest chain, one, two
carbons so it is ethan-- and
you don't call it ethanoic
acid anymore.
You call it ethanoate,
just like that.
Now, the next one, and we
haven't seen this one before,
and it looks complex, but when
you really break it down into
its constituents,
it's not so bad.
So let's say we have a molecule
that looks like this.
So we have one acyl group bonded
to an oxygen, which is
bonded to another acyl group.
So it's almost like you have two
carboxylic acids that have
been joined together.
And you really do have two
acyl groups joined by an
oxygen here.
This is called an anhydride.
And they look very complex, but
you just have to realize
they're two carboxylic acids
attached to each other and
usually the same one.
Most anhydrides you're going
to see in organic chemistry
are formed from the same
carboxylic acid, so how ever
many carbons you have on this
end, you're normally going to
have on this end.
So the way the name these is you
name it just the same way
that you would have named the
carboxylic acid, but instead
of writing the word acid, you
write the word anhydride.
So this right here would
be acetic anhydride.
It's derived from acetic acid.
This right here is
acetic anhydride.
Or the systematic name is, we
have one, two carbons so it's
ethanoic anhydride.
And just to make things clear,
if this molecule instead of
that, if we had something that
looked like this, where the
carbons chains on either
end had three carbons.
One, two, three, one,
two, three.
We would call this propanoic
anhydride.
In the unusual circumstance, and
it is unusual, where you
would see different carbon
chains here, you would list
each of them.
So if this had two here and
three here, it would be
ethanoic propanoic anhydride.
But that is very,
very unusual.
Normally, these carbon chains
on either end of-- or both
acyl will groups will contain
the same number of carbons.
Now, the last carboxylic acid
derivative that you should
know about, and we've already
seen it, are the acyl halides,
and, in particular, the
acyl chlorides.
So let me draw it
right over here.
So you have your acyl group
right there and then it is
bonded to a chlorine and this
right here is an acyl
chloride, maybe the most
intuitive name.
This right here is an acyl
group and then you have a
chlorine, so it's an
acyl chloride.
And we've seen this exact
acyl chloride.
It's derived from acetic acid,
so this is acetyl chloride.
But if you wanted to give it
its systematic name, and we
haven't seen it's systematic
name before, we have one, two
carbons so it is ethanoyl.
This tells us that we are
dealing with an acyl group.
Ethanoyl chloride is how
we would name this.
And if this had three
carbons, it would
be propanoyl chloride.
So, hopefully, that gives you
at least a good introduction
to the differences in structures
of all these groups
and an introduction
to naming them.
In the next video, we'll talk
a little bit about the
relative stabilities and then
it'll give you good intuition
on which direction a
reaction might go.
Are you more likely to go from
amide to an acyl chloride or
from an acyl chloride to an
amide or anything in between?