GB777688A - Polyhydrophenanthrene compounds and their preparation - Google Patents

Abstract

The invention comprises compounds having the formula: <FORM:0777688/IV(b)/1> in which the 7-position is occupied by either a divalent group convertible to a single keto group by acid hydrolysis, e.g. a cyclic ketal, or by a pair of univalent groups together convertible to a single keto group by acid hydrolysis, e.g. a non-cyclic ketal, and compounds having the formula: <FORM:0777688/IV(b)/2> in which the 7-position is occupied by a univalent group which is convertible to keto by hydrolysis, e.g. an enol ether (in both formul (a) and (b), R1 represents an alkyl group) and the corresponding 7-keto compounds, and their preparation (a) by ozonizing compounds corresponding to formul (a) and (b) bearing a 2-methallyl substituent and reducing the ozonide so produced with a mild reducing agent, e.g. zinc and acetic acid or hydrogen in the presence of a platinum catalyst; or (b) by reacting with per-iodic acid a compound corresponding to formul (a) and (b) bearing a 2-b ,g -dihydroxy-isobutyl substituent. The ozonization may be effected in methanol at about - 80 DEG C. The oxidation with per-iodic acid may be effected in ethanol or tetrahydrofuran in the presence of pyridine. Compounds blocked in 7-position may be converted to 7-keto compounds with acid, e.g. p-toluene sulphonic acid, perchloric acid and hydrochloric acid. Examples disclose the production of several stereoisomers of 1-carbomethoxymethyl - 2 - acetonyl - 4 - keto-2,4b - dimethyl - 7 - ethylenedioxy - 1,2,3,4,4a, 4b,5,6,7,8,10,10a - dodecahydrophenanthrene and of the corresponding 7-keto compound. Specifications 763,208, 777,686, 777,687 and 777,689 also are referred to.