GB666106A - Process for the manufacture of compounds with semi-cyclic double bond - Google Patents

Abstract

Compounds with semi-cyclic double bond are manufactured by reducing an a : b -unsaturated cycloalkenyl-carbonyl compound by the Wolff-Kishner method, e.g. by the action of hydrazine and alcoholates of mono- and bi-valent metals (especially of alkali metals, e.g. sodium ethoxide), in the presence or absence of solvents (preferably anhydrous, e.g. aliphatic alcohols such as ethanol or di- or tri-ethylene glycol, or dioxane), or by heating with an aqueous solution of hydrazine, an alkali hydroxide and a high-boiling solvent (e.g. di- or tri-ethylene glycol), or by forming nitrogen-containing derivatives (e.g. hydrazones, oximes or semi-carbazones) of the carbonyl compounds and further treating these correspondingly. Examples describe the reduction of: (1) and (10) D 2-2-formylcholestene to 2-methylenecholestane; and (2) and (4) D 1-cyclopentene aldehyde to methylenecyclopentane; (3) D 5:16-3b -acetoxypregnadiene-20-one to D 5 : 17-3b -acetoxypregnadiene (hydrolysed acetoxy groups being reacetylated with acetic anhydride and pyridine); (5) D 1 - cycloheptene aldehyde to methylenecycloheptane; (6) D 1-cyclopentadecene aldehyde to methylenecyclopentadecane; (7) b -cyclocitral to 2 : 2 : 6-trimethyl-1-methylenecyclohexane; (8) D 3-1 : 1-dimethyl-2-hydroxymethyl-3-formylcyclohexene to g -cyclogeraniol; (9) D 3-1 : 1-dimethyl-2-(31-hydroxy p - 11 - butyl) - 3 - formylcyclohexene to g - dihydroionol; (11) D 1 - tetrahydroacetophenone to ethylidenecyclohexane. Reference is also made in general to the reduction of D 16 - androstenyl - 17 - aldehydes and -ketones (which may be further substituted, e.g. by free, etherified or esterified hydroxy groups, especially in 3-, 11-, 12-, 14- or 21-position, and may contain additional double bonds, e.g. in 5 : 6-, 11 : 12- or 14 : 15-position), any further keto groups present being likewise reduced or temporarily protected by conversion to enol derivatives or acetals. The products of this embodiment of the invention are useful intermediates for the preparation of 17-keto compounds of the androstane series by oxidative splitting of the semi-cyclic double bond. A sample has been furnished under Sect. 2 (5) of D 5 : 17-3b -acetoxypregnadiene prepared by heating D 5 : 16 - 3b - acetoxypregnadiene - 20 - one semicarbazone with a solution of sodium in ethanol in a sealed tube, reacetylating the hydrolysed acetoxy group with acetic anhydride and pyridine, and purifying the product by chromatography and crystallization.