GB1118335A - A process for the manufacture of carbocyclic compounds - Google Patents

Abstract

Compounds of the Formulae (I), (II) and (III) <FORM:1118335/C2/1> (wherein X is H, lower alkyl, lower alkylthio or lower alkanoyl-thio in the 6-position, the numbering being that of steroids with ring A missing, or H, halogen, lower alkyl, lower alkylthio or lower alkanoyl-thio in the 7-position; and Z is a grouping of the formula (IVa) or (IVb) in which R1 is OH or lower alkanoyloxy; R2 is H or lower alkyl; or R1 and R2 together are a 17b -hydroxy-17a -(lower alkanoic acid) lactone group or an oxo group; R3 is H, lower alkyl, OH or lower alkanoyloxy; R30 is H, F, lower alkyl, OH or lower alkanoyloxy; R4 is H, halogen, lower alkyl or OH; and R5 is H, halogen or OH; the word "lower" referring to groups of at most 6 carbon atoms) are prepared by pyrolysing compounds of the formula (V) (wherein Y is H or an esterified OH group capable of being eliminated) or an alkali metal salt thereof in the presence of a basic nitrogen-containing organic solvent, a mixture of compounds (I) and (II) being obtained when Y is H, and compounds (III) being obtained when Y is esterified OH. Hydroxy and keto groups may be protected by esterification, etherification and ketalization and subsequently regenerated. In the products hydroxy groups may be oxidized to keto groups. Examples are given, and des-A-pregn-9-ene-5,20-dione is purified via its disemicarbazone. Lithium salts of compounds of the Formula (V) used as starting materials are prepared from the free acids and lithium methylate.