A rapid and simple one-pot procedure for the synthesis of 3β-acetoxy-5α-hydroxy-6-oxo steroids

Abstract

A fast one-pot procedure for the synthesis of 5α-hydroxy-6-oxo steroids is described. Epoxidation of 3β-hydoxy-∆ 5 steroids followed by oxidative cleavage of the resulting epoxide with aqueous CrO 3 lead to the desired compounds without affection of labile side chains.

Straightforward synthesis of unnatural poly-oxygenated steroid sapogenins

“…Thus, treatment of diosgenin acetate (1) with NaNO2 and BF3•Et2O in acetic acid followed by column chromatography in neutral alumina (Brokmann activity III) following Barton´s procedure afforded the ketone 2 that was subsequently converted into the acetylated ketol 3 employing our simple one-pot procedure which includes epoxidation with meta-chloroperoxybenzoic acid (mCPBA) followed by oxidative cleavage of the oxirane ring with CrO3. 28 Hydrolysis of the acetate at position C-3 afforded the target dihydroxylated ketone 4 that was converted into the unsaturated ketol 5 by tosylation in pyridine followed by elimination using treatment with LiBr and Li2CO3 in refluxing DMF. Subsequent dihydroxylation employing OsO4 and N-methylmorpholine N-oxide (NMO) as co-oxidant in TMF afforded a mixture of the target trihydroxylated diketone 6 as the maJor compound, accompanied by its 2,3-diastereomer 7 that were separated by column chromatography (Scheme 2).…”

Synthesis, structural analysis and antiproliferative activity of some novel D-homo lactone androstane derivatives

“…Compounds 1-4 were synthesized as described in our previous work. 5,25 In this paper we report a rapid and simple one-pot procedure 26 which was modified from our previous work 25 for the synthesis of compound 4 from starting compound 1. Treatment of 4 with thionyl chloride (absolute pyridine, 0 uC for 2 h) gave 17-oxa-Dhomoandrost-4-ene-6,16-dion-3b-yl acetate (5).…”

Unambiguous assignment of 13C NMR signals in epimeric 4,5-epoxy-3-oxo-steroids assisted by X-ray diffraction and gauge invariant atomic orbitals calculation of absolute isotropic shieldings

“…As a part of our ongoing program on the synthesis of potentially bioactive steroids, [8][9][10][11] we require the unambiguous NMR characterization several pairs of epimeric epoxides derived from different 4-en-3-oxo-steroids that are being employed as synthetic precursors. Herein we report on the unambiguous 13 C NMR assignments of series of epimeric 4,5-epoxy-3-oxo-steroids, assisted by X-ray diffraction and Gauge Invariant Atomic Orbitals Calculation of Absolute Isotropic Shieldings.…”