A kind of synthetic method of bromiesoval

Abstract

The invention discloses a method for synthesizing bromisoval. The first step: Isovaleric acid reacts with bromine under the catalysis of phosphorus tribromide to generate α-bromoisovaleric acid; the second step: after the first step, the product is directly pressed into the acid bromide without separation. In the tank, add phosphorus tribromide and bromine, and continue the reaction to generate α-bromoisovaleryl bromide. After the reaction, collect the 85-95℃ / 20-30mmHg fraction by distillation under reduced pressure and temperature to obtain α-bromoisovaleryl bromide Valeryl bromide; the third step: condensation of α-bromoisovaleryl bromide and urea to obtain bromisoval. The invention has the advantages of high product yield, high purity, less impurities, low cost, easy production control, hydrogen bromide gas generated in the production process is absorbed by water to obtain hydrobromic acid, which can be comprehensively utilized, and the discharge of three wastes is reduced.

Description

technical field

[0001] The invention relates to a method for synthesizing bromisoval. It belongs to the technical field of drug synthesis. Background technique

[0002] Bromisoval is an old sedative-hypnotics, which belongs to the straight-chain urea class of sedative-hypnotics. Because of its definite curative effect and advantages such as small side effects, it is still used clinically. Its preparations include tablets, injections and other compound preparations. Its traditional synthetic method is that isovaleric acid reacts with bromine under the catalysis of red phosphorus to generate α-bromoisovaleryl bromide, and then condenses with urea to obtain bromidesoval. This method has low yield (29%) and low cost. High; Japanese Patent Publication No. 54-39019 and No. 54-27527 two patents use α-bromoisovaleryl chloride as raw material to condense with urea to obtain bromisoval. Although the synthesis yield of this method is high, the raw material α -Bromoisovaleryl chlorid...