Chapter 22.SE, Problem 65AP

Interpretation Introduction

Interpretation:

The synthesis of sodium pentothal is to be given.

Concept introduction:

Removal of both the hydrogens of the active methylene group in malonic ester by treating with sodium ethoxide and then treating the enolate ions with alkyl halides will yield the dialkylated product.

The steps involved in the reaction of the dialkylated product with thiourea are i) Nucleophilic attack of nitrogen of thiourea on the carbonyl carbon of the dialkylated ester ii) Elimination of the ethoxide ion as ethanol iii) Another nucleophilic attack by second nitrogen of thiourea on the carbonyl of the other ester group iv) Elimination of another ethanol.

To give:

The synthesis of sodium pentothal using thiourea and a dialkylated ester.