GB833582A - New steroid esters and the preparation thereof - Google Patents

Abstract

The invention comprises 3,17-esters of oestradiol, 17-esters of testosterone and 17-esters of 19-nor-testosterone, and 21-esters of cortisone, hydrocortisone, prednisone and prednisolone (in each case the ester group or groups are derived from glycine, alanine and phenylalanine), and acid addition salts of said esters. The esterification is carried out with the aminocarboxylic acid which may be in one of its optically active forms or as a racenate, the amino group being protected, e.g. by means of the carbobenzoxy group. Thus the esterification may be carried out with an N-carbobenzoxy amino-acid in the presence of a dehydrating agent. e.g. ethoxyacetylene, or by use of the corresponding acid anhydride or acid chloride, preferably in the presence of an organic base, e.g. a tertiary base such as pyridine or quinoline. After the esterification the carbobenzoxy group from the resulting N-carbobenzoxy amino-acid ester of the above steroid compounds can be split off by catalytic reduction or by treatment with a hydrohalogenic acid such as hydrobromic acid, in which case the corresponding hydrohalide salt is formed. The process may be modified in that any oxo groups in the reactants may be protected during esterification such as by ketalization, e.g. to form an ethylenedioxy group. A number of detailed examples are given.