ISSUE:

Hello everyone.

I post this topic to see if you could help me in the mechanism of the synthesis of barbituric acid. I only know that it proceeds by reaction between urea and diethyl malonate, in the presence of a base such as sodium ethoxide and ethanol as the reaction medium. Thank you for your time.

Hello stimpy.

The most common syntheses for barbiturate acid are the one you mention and the one that occurs between malonic acid and urea, the latter is a direct condensation, where amides (lactams) are formed.
On the other hand, the one you mention, passes through the Knoevenagel condensation reaction in its first section and then through the Baeyer condensation, as I indicate in the following scheme. Greetings;)

Could you explain to me what happens in the beayer condensation, I don't understand it well