Chapter 21, Problem 21.59P

Interpretation Introduction

(a)

Interpretation:

Gabriel synthesis of primary amines involves hydrolysis under basic conditions to release the amine. The amine can also be released by hydrolysis under acidic condition; the complete, detailed mechanism accounting for the reaction is to be drawn.

Concept introduction:

Gabriel synthesis produces a primary amine from a corresponding alkyl halide.

The ester is hydrolyzed to the carboxylic acid under acidic conditions, so strong base should appear in the mechanism. Water is the nucleophile, and the leaving group is a molecule of ethanol. Proton transfer steps are incorporated to avoid the appearance of strong bases.

Interpretation Introduction

(b)

Interpretation:

Gabriel synthesis of primary amines involves hydrolysis under basic conditions to release the amine. The amine can also be released by hydrolysis under acidic condition; the complete, detailed mechanism accounting for the reaction is to be drawn.

Concept introduction:

In Gabriel synthesis, phthalimide is first treated with a strong base such as potassium hydroxide, followed by an alkyl halide. Subsequent hydrolysis using hydroxide then liberates the primary amine. Phthalimide also releases the primary amine when treated with hydrazine where hydrazine act as a nucleophile in nucleophilic addition step and amine acts as the leaving group in nucleophilic elimination step.