- Asymmetric Isopropylation of Steroidal 24-Aldehydes for the Synthesis of 24(R)-Hydroxycholesterol
-
The chiral β-amino alcohols-catalyzed addition of diisopropylzinc to steroidal 24-aldehydes successfully provided 24(R)-hydroxycholesterols in good yields with high diastereoselectivities, which are synthetic intermediates of 1α-24(R)-dihydroxyvitamin D3
- Okamoto, Makoto,Tabe, Masayasu,Fujii, Takao,Tanaka, Toshio
-
p. 767 - 778
(2007/10/02)
-
- STEROID COMPOUNDS OF MARINE SPONGES. I. STEROLS OF Esperiopsis digitata
-
From extracts of the Far Eastern sponge Esperiopsis digitata, by column chromatography on silica gel we have isolated three fractions of steroid compounds.The fractions isolated have been analyzed with the aid of TLC, GLC-MS, PMR, and 13C NMR.The least polar fraction (1) had a Rf value identical with that of cholesterol and represents the total free steroids.After argentation column chromatography, 13 components were identified in it, the main one being cholesterol.The more polar fraction (2) consisted of a combination of 3β-hydroxychol-5-en-24-al and 3β-hydroxy-24-norchol-5-en-23-al.The most polar of the fractions isolated - fraction (3) - consisted of a single component which was identified as cholesta-5,25-diene-3β,24ξ-diol.
- Shubina, L. K.,Makar'eva, T. N.,Boguslavskii, V. M.,Stonik, V. A.
-
p. 704 - 709
(2007/10/02)
-