GB729759A - Improvements in or relating to steroids - Google Patents

Abstract

The invention comprises cyclopentanophenanthrene compounds of the general formula <FORM:0729759/IV (b)/1> wherein R represents hydrogen or an alkyl or acyl radical and R1 represents the radical =CHO Acyl or represents <FORM:0729759/IV (b)/2> , and a process for the preparation of a 3-hydroxy-, 3-alkoxy- or 3-acyloxy-7,8-nuclear mono-unsaturated steroid containing a substituent of the formula <FORM:0729759/IV (b)/3> at the 17-position by selectively oxidizing a 7 : 8-nuclear monounsaturated steroid having a 22 : 23-alkenyl-type C17 substituent with ozone (preferably in a substantially inert solvent) and reductively cleaving the resulting ozonide to form the C17 aldehyde substituent. The process may be extended either by acylating the C17 aldehydic substituent to form an enol ester and the resulting enol ester may be oxidized, e.g. with ozone, to form a 20-ketone, or by oxidizing the C17 p aldehydic substituent, e.g. with chromic acid in strong sulphuric acid, to form the corresponding carboxylic acid. Compounds having a 22 : 23-alkenyl type C17 substituent which may be used in the above process are 5-dihydroergosterol and its esters and ethers such as 5-dihydroergosteryl acetate, a -spinasterol and its ethers and esters, and chondrillasterol and its esters and ethers. Suitable esters are the acetate, propionate and benzoate esters and suitable ethers are the methyl and ethyl ethers. The reaction with ozone may be carried out in an inert solvent such as chloroform or methylene chloride, and a tertiary base such as pyridine, quinoline or triethylamine may be present. The reaction temperature may be as low as -80 DEG C., the preferred temperature being about 0 DEG C. The ozonide may be reductively cleaved with acetic acid and zinc dust. Esters of the acids derived from the 17-aldehydic compounds are also referred to. In the examples 3b -acetoxybisnorallo-7-cholenaldehyde and the semicarbazone thereof, the enol acetate of 3b -acetoxybisnorallo-7-cholenaldehyde, 3b -acetoxyallo-7-pregnen-20-one and the semicarbazone thereof and 3b -acetoxybisnorallo-7-cholenic acid are prepared.