[chynagrl]

Hi,

I am trying to work out a reaction of a carboxylic acid with DCC and CH3CN. I think it's supposed to produce an anhydride, but what is the mechanism for this? The only thing I can think of right now is that the DCC deprotonates the alcohol group on the carboxylic acid. Attached is a picture of what I have right now (sorry I don't have Chemdraw/chesketch/etc).

Thanks a bunch!
chynagrl

[azmanam]

start here:

http://en.wikipedia.org/wiki/Carbodiimide
http://orgchem.chem.uconn.edu/2444f2008/111008.pdf

[Dynamic]

You are probably trying to make an ester.  You also need a strong base (like 4-dimethylaminopyridine) for this to work well.  In the first step the DCC (dicyclohexylcarbodiimide) adds to the carboxylic acid and forms an intermediate compound.  The DCC part of the molecule is a good leaving group and produces dicyclohexyl urea and an ester in the presence of an alcohol and a strong base like 4-DMAP.  

I've even produced a t-butyl ester using t-butanol with this method.

edit.  By the way, from the title of your post it appears that you might be confused about the CH3CN which is a solvent in this reaction... not a reactant.  The dicyclohexyl urea is not very soluble in cold acetonitrile.