[lutesium]

How can Acetic Acid Diethoxy Methyl ester Catalyze the Reaction of
=======
N-(4-chloro-5-formamido-6-((1S,3R)-3-(hydroxymethyl)cyclopentylamino)pyrimidin-2-yl)acetamide
===to===
N-(6-chloro-9-((1S,3R)-3-(hydroxymethyl)cyclopentyl)-9H-purin-2-yl)acetamide

Is that compound a dehydration Catalyst???

Thank you very much

[orgopete]

No, it is a reagent. I have drawn out the missing pieces for this reaction showing the role of the methyl diethoxyacetate. I am presuming there is an acid present also, but I don't know the reaction conditions.

[lutesium]

Thanks for your reply but I stilll can't understand the mechanism (anyways you didn't indicate him)!!!
There is no reaction condition only heat!!!

[lutesium]

Oh OK!!! I've understood how the reaction proceeds now!!! But why and how does Methyl diethoxyacetate give off his esters so easily???

[orgopete]

Let me concede that another mechanism may be operating also. The mechanism I drew assumed an acid catalyst to absorb water in forming the aldehyde. The reaction could also occur under basic conditions and form the carboxylic acid and methanol (to absorb the water). (I would not have expected this mechanism to be in operation as basic conditions also invite ester exchange and other possible reactions.)

If the reaction were carried out with a notable catalyst, it is easier to draw a rational mechanism. However, some reactions almost defy rationality. If ammonium phthalate or phthalic acid with urea is heated to high temperature, phthalimide forms. These conditions defy belief that it is an acid catalyzed reaction, but it is difficult to rationalize the formation of product without acid catalysis.