Alpha-acylamino-crotonic and butyric acid derivs. - intermediates for direct synthesis of D-2-amino-butanol which is a precursor for ethambutol

摘要

Amides of formulae (CH3CH=C(R1)NHCOR2(III) and CH3CH2C(R1)HNHCOR2 (IV) are new. In the formulae, R1 is COOH or 2-7C alkoxycarbonyl; and R2 is H, 1-6C alkyl, phenyl (opt. substd. by halo or 1-3C alkyl), amino (opt. substd. by 1-6C alkyl), amido, 1-6C alkoxy, phenoxy (opt. substd. as phenyl) or 2-7C alkoxycarbonyl. Esp. pref. cpds. have R2=H, CH3, isopropyl, phenyl, NH2, amid, methoxy, phenoxy or carbomethoxy. Amides are intermediates in a direct synthesis of d-2-aminobutanol (I) which avoids the need for a resolution stage and recycling of the unwanted isomer. (I) is an intermediate for ethambutol.