GB779498A - Process for the partial removal of oxo groups from steroid compounds - Google Patents

Abstract

In a process for the manufacture of monooxo-compounds of the steroid series an a -dioxocompound of the steroid series or an enol or enolate thereof is heated with hydrazine, hydrazine hydrate or a hydrazine salt or with semicarbazide or a salt thereof, e.g. acetate, chloride or sulphate, in the presence of an alkali metal hydroxide or alcoholate at a temperature at which nitrogen is evolved and which does not exceed 160 DEG C. As starting materials, steroids with the vicinal oxo groups in the 2:3-, 3:4-, 6:7-, 16:17-, 20:21- and especially the 11:12-positions and also the corresponding enols such as D 9:11-11-hydroxy-12-ketones or d 15-16-hydroxy-17-ketones or their enolates such as metal enolates, enol-acylates or enol-ethers are suitable. The steroids may be of the oestrane, androstane, testane, aetiocholane, pregnane, spirostane, furostane, bufostane, cholane, cholestane, nor- or bisnor-cholestane series. Preferably, the reaction is carried out at 120 DEG to 150 DEG C. in a mono- or poly-oxy compound as solvent. In examples: (1) 3a -hydroxy-11:12-diketo-cholanic acid is heated at 135-145 DEG C. with caustic soda and hydrazine hydrate in ethylene glycol to give 3a -hydroxy-11-ketocholanic acid. Similarly, (2) D 2:11-3a :11-dihydroxy - 12 - cholenic acid - 3 - acetate is converted to 3a - hydroxy - 11 - keto - cholanic acid; (3) D 9:11-3a :11 - diacetoxy - 12 - keto - cholenic acid methyl ester is converted to 3a -hydroxy-11-keto-cholanic acid (with intermediate treatment with acid); (5) 3b -hydroxy-11:12 - diketo - iso - allospirostane is converted to 3b - hydroxy - 11 - keto - iso - allospirostane. In Example (4) D 23-3a -acetoxy-11:12-diketo-24:24-diphenyl-cholene is similarly treated, and the reacted product is acetylated with acetic anhydride and pyridine to form D 23-3a -acetoxy-11-keto-24:24-diphenyl cholene. Starting compounds. D 9:11 - 3a :11 - Dihydroxy - 12 - keto - cholenic acid 3-acetate is prepared by heating 3a -hydroxy-11:12-diketocholanic acid with acetic acid. D 23-3a -acetoxy-11:12 - diketo - 24:24 - diphenyl - cholene is prepared by adding a mixture of D 23-3a -acetoxy - 12b - hydroxy - 11 - keto - 24:24 - diphenyl-cholene acetic acid and chlorobenzene to a heated mixture of bismuth trioxide, acetic acid and chlorobenzene and distilling off solvent. The mother liquor after evaporation and acetylation also yields D 23-3a -acetoxy-11:12-diketo-24:24-diphenyl-cholene-11 -enolacetate.