Synthesis of dl-2-amino-1-butanol

Abstract

DL-2-Amino-1-butanol, as the free base or a salt, for resolution to d-2-amino-1-butanol, for the synthesis of ethambutol hydrochloride, d,d'-2,2'-(ethylenediimino)di-1-butanol dihydrochloride, is produced in high purity and good yields by the reaction of butene-1, a nitrile, preferably an excess of acetonitrile, and chlorine to form N-[1-(chloromethyl)propyl]acetimidoyl chloride which is hydrolyzed to dl-2-amino-1-butanol hydrochloride. This can be isolated as the hydrochloride, or free base, or a mixture, resolved with L(+)- tartaric acid and the d-2-amino-1-butanol reacted with ethylene dichloride and then hydrochloric acid to form ethambutol hydrochloride. A minimum of by-products which are conveniently split out permits the economical synthesis of a pharmaceutical grade product.

Dependencies are inferred from the claim text.