| abstract |
The invention relates to products 1: where R 1 is hydrogen, alkyl (1 to 4 C) optionally substituted by an oxygenated or nitrogen function or by a halogen, where R 1 is alkenyl or alkynyl (2 to 4 C), R 2 is alkyl (1 to 4 C) , the nuclei A, B, C, and D optionally carry one or more double bonds and are optionally substituted by one or more OH, CO, Halogens, alkyl or alkoxy (1 to 4 C), alkenyls or alkynyls (2 to 4 C ); their preparation from 17 (20) ene 20-formamido 21-oates corresponding alkyl derivatives and their application to the preparation of the corresponding 17-hydroxy acetyl derivatives, useful derivatives in the pharmaceutical industry. |