Synthesis of 5alpha-pregna-1,20-dien-3-one

5ALPHA-Pregna-1,20-dien-3-one has been synthesized from 3beta-hydroxy-5alpha-pregnan-20-one by reaction of the tosylhydrazone with butyllithium to introduce the vinyl moiety. Oxidation of the alcohol and treatment of the anion of the resulting ketone with benzeneselenenyl chloride gave the 2-phenylseleno derivative. This afforded the conjugated enone on oxidative elimination.     

1alpha,3beta,5beta-trihydroxy-24-methylenecholestan-6-one: a novel steroid from a soft coral Sinularia gibberosa

A novel steroid, 1alpha,3beta,5beta-trihydroxy-24-methylenecholestan-6-one (gibberoketosterol) (1), along with four known steroids, was isolated from the lipophilic extracts of a Taiwanese soft coral Sinularia gibberosa. The structure of the new metabolite was determined on the basis of extensive spectral analyses and chemical reaction. The relative stereochemistry of gibberoketosterol was established by the NOESY experiments and analysis of the pyridine-induced deshielding effect of the axial hydroxy groups. Gibberoketosterol is the first example of 1alpha,3beta,5beta-trihydroxy-6-oxosteroids isolated from natural sources and was found to exhibit a moderate cytotoxicity against the growth of Hepa59T/VGH cancer cells.     

5,8-Epidioxysterols and related derivatives from a Chinese soft coral Sinularia flexibilis

Chromatographic separation of the methanolic extract of the marine soft coral, Sinularia flexibilis, resulted in the isolation and characterization of four new sterols, 5alpha,8alpha-epidioxygorgosta-6-en-3beta-ol (1), 5alpha,8alpha-epidioxygorgosta-6,9(11)-dien-3beta-ol (2), 22alpha,28-epidioxycholesta-5,23(E)-dien-3beta-ol (3) and its C-22 epimer (4), along with nine known sterols. The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, 1H and 13C NMR, HMQC, HMBC, and NOESY) analyses.     

Towards an ecdysone synthesis. 20 -acetoxy-5 -pregna-2,7-dien-6-one

Pregnenolone (3β-hydroxy-5-pregnen-20-one) was converted to 20β-acetoxy-3, 5-cyclo-5α-pregnan-6-one by existing procedures. This compound was ring opened with bromine, and the resultant 3, 5-dibromide was subsequently rearranged to the 3, 7-dibromide. Dehydrohalogenation of the latter gave 20β-acetoxy-5α-pregna-2, 7-dien-6-one. This substance is of interest as intermediate for the synthesis of ecdysone.     

Marine sterols. XIII. Isolation and synthesis of 1β,3β,5,6β-tetrahydroxy-5α-androstan-17-one from the soft coral

A minor C₂₇ sterol, glaucasterol, was isolated from the soft coral Based on the spectroscopic evidence and the correlation to cholestanol and 26-nor-27-homocholestanol, its structure was proposed to be 24ξ, 25ξ-24,26-cyclocholesta-5,22E-dien-3β-ol ( ), the first example of a natural C₂₇ sterol having a cyclopropane ring in the side chain.     

3-caren-5-one from Kaempferia galanga

The rhizomes of Kaempferia galanga afforded a new monoterpene ketone whose structure was elucidated as 3-caren-5-one by spectroscopic means.     

Production of 20-carboxy-pregna-1,4-dien-3-one from sterols by mutants of Rhodococcus sp

By selection of microorganisms which preferentially attack the side-chain of either cholesterol or β-sitosterol (campesterol) we isolated five mutants of Rhodococcus sp. strain k-3 was obtained from the wild-type strain MIL 1037 and μ-9, μ-11, and μ-12 from MIL 1038, by mutagenic treatment and produced preferentially 20-carboxy-pregna-1,4-dien-e-one from β-sitosterol (campesterol) or cholesterol in good yield. The other mutant, μ-7, isolated from the wild-type strain MIL 1038 produced a new compound identified as 7aβ-methyl-1β-[1′,5′-dimethyl-6′-hydroxy-hexyl]-5-oxo-3aα-hexahydro-4-indanpropionic acid from cholesterol. A temporary accumulation of this compound was observed during the transformation of cholesterol. This compound could be used as an intermediate for the chemical synthesis of steroids with unnatural configurations.     

The reduction of 5 alpha-cholestan-3-one and 5 beta-cholestan-3-one by some boranes and hydroborates.

This paper describes the high yield synthesis of 5 alpha-cholestan-3 alpha-ol and 5 beta-cholestan-3 beta-ol by the reduction of 5 alpha- and 5 beta-cholestan-3-one using using potassium and lithium-tri-sec-butyl-hydroborates as reducing reagents. Attempts to obtain the same alcohols using other bulky boranes resulted in the equatorial products.