A Convenient Large Scale Synthesis of O-Benzylhydroxylamine

Abstract

Synthetically useful O-benzylhydroxylamine can be conveniently prepared in large scale by reaction of N-hydroxyphthalimide and benzyl chloride in phase transfer conditions, followed by acidic hydrolysis of N-benzyloxyphthalimide. The overall yield is over 65%.

Notes

The reaction resulted in being too slow at room temperature and in addition the yield was unsatisfactory.

The crude product can be easily purified with high yield (95%) by filtration of a dichloromethane solution through a pad of silica gel. Alternatively, crystallization with ethanol gave, with a 85% yield, a pure product having m.p. = 143–145°C.

With a longer reaction time (4 hours) the yield remained almost unaffected.