GB926861A - ª -amino-ª -hydroxy carboxylic acid amides and process for preparing them - Google Patents

Abstract

The invention comprises alpha-amino-beta-hydroxy-butyric acid amides substituted on the amido nitrogen atom by an aliphatic hydrocarbon radical R which is attached to the nitrogen atom by a tertiary carbon atom, and acid-addition salts thereof; and the preparation thereof by treating a compound of the formula CH3COCH2CONHR (prepared from diketene and the amines NH2R) with nitrous acid or reacting it with an aryl diazonium salt, and reducing the product. The products of the reaction with nitrous acid are a -isonitroso derivatives of the keto-amides of the above formula, and they may be reduced in stages, first by reduction with for example, nascent-hydrogen to a compound of the formula CH3COCH(NH2)CONHR and then to the required product with, for example, sodium or aluminium amalgam and an alcohol and sodium borohydride or by catalytic hydrogenation or electrolytically. Before this final reduction, the intermediate amine is desirably acylated to give a compound of the formula CH3COCH(NHAc) CONHR (wherein Ac is an acylating group such as an acetyl, propionyl, benzoyl or phenylacetyl group) which on reduction gives a compound of the formula CH3CH(OH) CH(NHAc)CONHR from which the required final product is obtained by hydrolysis. The products of the reaction with an aryl diazonium salt are a -arylazo derivatives of the keto-amide starting materials, which may then be reduced in stages by the same methods as are employed for the isonitroso compounds. Alternatively the reduction process of the invention may be effected in one stage, by catalytic hydrogenation, or electrolytically, or with nascent hydrogen or sodium borohydride. Detailed examples are given, one product being isolated in two isomeric forms. The amides of the invention, which have analgesic properties, may be incorporated in pharmaceutical compositions with the aid of suitable carriers. Specifications 816,225 and 828,694 are referred to.