Question

Identify the lettered intermediates in the following reaction scheme. This is an alternative method to synthesize amino acids, based on the Gabriel synthesis of 1° amines (Section 25.7A).

Short answer

Compound B which is N-alkylation is an intermediate of this reaction.

Step-by-step solution

Gabriel synthesis

In Gabriel synthesis, reaction is altered from primary alkyl halides to primary amines. It was named by Siegmund Gabriel who was a German chemist.Here, in this reaction, over alkylation is avoided.

Synthesis of primary amine

When diethyl adipate is treated with bromine followed by acetic acid, it gives$\text{Br-CH}{\left(\text{COOEt}\right)}_{\text{2}}$ , and when it is treated with potassiumphthalimide, it forms a Nitrogen alkylation.

Nitrogen alkylation is an intermediate that reacts with$\text{NaOEt}$ and${\text{ClCH}}_{\text{2}}{\text{CH}}_{\text{2}}{\text{SCH}}_{\text{3}}$ forms a compound C which on further reaction with sodium hydroxide followed by hydrolysis under heat forms a product.

Formation of intermediates in the reaction scheme