- Stereochemically Controlled Synthesis of Steroid Side Chains: Synthesis of Desmosterol
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(20R)-Desmosterol, a versatile intermediate for the synthesis of vitamin D metabolites and numerous other steroids having a side chain modified at C-24 and/or C-25, can be synthesized stereospecifically and efficiently by starting from the readily available 16α,17β-epoxypregnenolone and employing the potassium-assisted oxy-Cope rearrangement as a key stereodirecting process at C-20.
- Koreeda, Masato,Tanaka, Yoshio,Schwartz, Anchel
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- A new highly stereoselective synthesis of cerebrosterol, an agonist of the nuclear receptor LXRs
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The title compound, cerebrosterol 1, was synthesized stereoselectively (97% d.e.) in 41% overall yield from methyl hyodeoxycholanate 2 in 10 steps with desmosterol acetate 8 as the key intermediate and the modified Sharpless asymmetric dihydroxylation as the key step.
- Zhou, Xiang-Dong,Zhou, Wei-Shan
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- An enzyme-based formaldehyde assay and its utility in a sponge sterol biosynthetic pathway
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An enzyme-based assay has been developed and utilized to confirm the production of formaldehyde in the dealkylation of sterol side chains in a marine sponge. The enzyme used in the assay, formaldehyde dehydrogenase, is NAD+ dependent, and the assay measures the production of NADH by determining the increase in fluorescence at 460 nm.
- Kerr, Russell G.,Kelly, Kathleen
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- Synthesis of 24-functionalized oxysterols
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The syntheses of (24S)-24,25-epoxycholesterol, (24S)-hydroxycholesterol, and 24-ketocholesterol are described. The compounds belong to oxysterols, which can be considered to be the modulators of cholesterol metabolism. The asymmetric hydroxylation of desmosterol acetate according to Sharpless was used as the key reaction in the stereoselective introduction of functionality in position 24.
- Khripach,Zhabinskii,Konstantinova,Khripach,Antonchick
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p. 257 - 261
(2007/10/03)
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- Stereocontrolled syntheses of 24(S),25-epoxycholesterol and related oxysterols for studies on the activation of LXR receptors
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Efficient syntheses are described of desmosterol (4), the corresponding 24(S),25 epoxide (6) and various analogs of 6 for evaluation as ligands and functional activators of LXR receptors.
- Corey,Grogan, Michael J.
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p. 9351 - 9354
(2007/10/03)
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- Synthesis of Cholesterol and Derivatives substituted in the Side chain
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The carbanion derived from 24-phenylsulphonylchol-5-en-3β-ol 3-tetrahydropyranyl ether (6) reacted with acetone to give the 24-phenylsulphonyl-25-hydroxycholesterol derivative (7a), which was reduced by sodium amalgam to a separable mixture of the labelled 25-hydroxycholesterol and cholest-5,24-dien-3β-ol (desmosterol) derivatives. Cholesterol has been obtained via a selective reduction of the Δ24-unsaturation in desmosteryl benzoate with di-imide, or more efficiently by reducing 25-hydroxycholesteryl 3,25-diacetate w ith litium in ethylamine, without significant loss of label.The labelled 24,25-dihydroxycholesterols were also prepared from desmosteryl benzoate.
- Kirk, David N.,Varley, Michael J.,Makin, Hugh L.J.,Trafford, David J.H.
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p. 2563 - 2567
(2007/10/02)
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- SIDE CHAIN MODIFIED STEROLS AS PROBES INTO INSECT MOLTING HORMONE METABOLISM. II: SYNTHESIS OF MONOFLUOROCHOLESTEROLS
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The hydroxylations of the cholesterol side chain at C-20, 22, and 25 are key terminal events in ecdysone biogenesis. We have prepared the C-20, C-22, C-24, and C-25 monofluorinated cholesterols as potential inhibitors of these hydroxylation events, and preliminary bioassay results in Manduca sexta are reported.The synthesis of -20-fluorocholesterol is also described.Although the 20-, 22-, and 25-monofluorocholesterols do not appear to affect larval growth and development, the 24-fluoro isomer shows a moderate retardation of growth and a modest increase in mortality.
- Prestwich, Glenn D.,Shieh, Hong Ming,Gayen, Apurba K.
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