A Concise Synthesis of 25-Hydroxycholesterol from Hyodesoxycholic Acid

Abstract

A simple, efficient and economical method has been developed for the synthesis of 25-hydroxycholesterol in seven steps from hyodesoxycholic acid with an overall yield of 39%. The preparation of the 3β-tetrahydropyranyloxychol-5-en-24-al from 3β-tetrahydropyranyloxychol-5-en-24-oic acid methyl ester with di-isobutylaluminium hydride was achieved instead of using the conventional two-step reaction, thus avoiding the use of the toxic oxidant CrO3. The terminal product was obtained by hydroxybromination of desmosterol with N-bromosuccinimide/H20, followed by reduction and deprotection of the halohydrins with LiAlH4. This simplified route gave an increased overall yield and used economical and environmentally benign reagents.

Bioconversion of vitamin D3 into calcitriol by Actinomyces hyovaginalis isolate CCASU- A11-2

“…The microbial conversion of vitamin D 3 has a lower cost than chemical synthesis; nevertheless, the order Actinomycetales (well known to establish vitamin D 3 bioconversion), namely the two genera Streptomyces and Amycolata , showed very few microorganisms capable of conducting this conversion (Sasaki et al 1991 , 1992 ; Sawada et al 2004 ; Kang et al 2006 ; Takeda et al 2006 ). Furthermore, traditional organic synthesis of the hydroxylated vitamin D3 derivatives is highly complex, which results in low yield (Andrews et al 1986 ; Jin et al 2018 ; Ryznar et al 2002 ). Fortunately, the stereo- and regiospecific introduction of the hydroxyl group of vitamin D3 by microorganisms exhibits glowing supremacy to bypass such obstacles.…”