49E - Organic Chemistry (Mcmurry)

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.

Step-by-Step Solution

Answer

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

Step 1: Synthesis of dialkylated intermediate

The synthesis of dialkylated intermediate is as follows,

                                                      Overall reaction 

Step 2: Mechanism

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

                                               Mechanism of the reaction