Method for synthesizing N, O-dimethylhydroxylamine hydrochloride

N,O-Dimethylhydroxylamine hydrochloride is used as a reagent in the preparation of 2-acyloxazoles from 2-oxazolemagnesium chloride and N-methoxy-N-methyl-3-oxo-butyramide from diketene. It is also used in amide coupling reactions to form Weinreb amides, which are useful in the Weinreb ketone synthesis. In addition, it is used in the preparation of an inhibitor of the NLS-derived BC peptides.

N,O-Dimethylhydroxylamine is a methylated hydroxylamine used to form so called 'Weinreb amides' for use in the Weinreb ketone synthesis. It is commercially available as its hydrochloride salt.

Synthesis

A method for synthesizing N, O-dimethylhydroxylamine hydrochloride, which comprises the following steps:

adding acetate and hydroxylamine salt into a reaction vessel at a room temperature, warming up to 20-50 DEG C, adding alkali, then carrying out heat preservation at a temperature of 20-50 DEG C, agitating and reacting for 1to 5 hours; controlling the temperature to be 30 to 50 DEG C, adding a methylating agent, carrying out heat preservation at a temperature of 30-50 DEG C after addition, agitating and reacting for 1-5 hours; then adding acid, heating to 50-100 DEG C and hydrolyzing for 1-4 hours; and finally adding alkali into a hydrolysate for neutralization, controlling the distillation time to be 2-8 hours at a normal pressure, adding hydrochloric acid salt in a fraction of the hydrolysate, concentrating under reduced pressure, cooling, filtering, washing and vacuum-drying to obtain the N, O-dimethylhydroxylamine hydrochloride.

The method for synthesizing the N, O-dimethylhydroxylamine hydrochloride is not applicable to poisonous and harmful raw materials, has the advantages of mild reaction condition, more simplicity in operation, higher yield, good product quality, more safety, less wastewater discharge and more environmental friendliness, and is suitable for industrial production.