Question

Aprobarbital, a barbiturate once used in treating insomnia, is synthesized in three steps from diethyl malonate. Show how you would synthesize the necessary dialkylated intermediate, and then propose a mechanism for the reaction of this intermediate with urea to give aprobarbital.

Short answer

Diethyl malonate is alkylated and then reacts the intermediate with urea to produce aprobarbital.

Step-by-step solution

Synthesis of dialkylated intermediate

The synthesis of dialkylated intermediate is as follows,

Overall reaction

Mechanism

The mechanism for the reaction of this intermediate with urea to give aprobarbital is as follows,

Mechanism of the reaction