- Kinetics of thermal [1,7A]-sigmatropic shift of hexafluoro vitamin D3 and vitamin D3 derivatives. Evaluation of conformations of the A ring affected by 1-OH and 3-OH groups
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The quantitative evaluation of the [1,7a]-sigmatropic rearrangement of vitamin D3 and its analogs affected by the conformations of the A ring using the 1H-NMR method was described. Although the side chain of the D ring had no effect on the hydrogen migration, the rearrangement was influenced by the hydroxy groups of the A ring.
- Igarashi, Jun-Etsu,Ikeda, Masahiko,Sunagawa, Makoto
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p. 1431 - 1436
(2007/10/03)
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- 1α-HYDROXY PREVITAMIN D3 AND ITS SELECTIVE FORMATION FROM 1-KETO PREVITAMIN D3
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An efficient method for the preparation of crystalline 1α-hydroxy previtamin D3 is described.Also the stereoselective reduction of 1-keto previtamin 9 is discussed; it was observed that with aluminium hydride 7 is the most abundant product.This stands in contrast with previously reported LiAlH4 and NaBH4 mediated reductions.
- Vanmaele, L. J.,Clercq, P. J. De,Vandewalle, M.,Halkes, S. J.,Overbeek, W. R. M.
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p. 1179 - 1182
(2007/10/02)
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- Calciferol and its Relatives. Part 28. A Stereoselective Synthesis of 1α-Hydroxyprecalciferol3 from 8-Hydroxymethyl-des-AB-cholest-8-ene
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8-p-Tolylsulphonylmethyl-des-AB-cholest-8-ene (1) and methyl (3S,5R)-3,5-bis-t-butyldimethylsilyloxy-2-methylcyclohex-1-enecarboxylate (2) were combined to give a 6-oxo-7-sulphone from which 1α,3β-diacetoxy-9,10-seco-cholesta-5(10),8-diene-6-yne (4) was obtained.Semihydrogenation and deacetylation gave 1α-hydroxyprecalciferol3 (6), which was converted by thermal isomerization into 1α-hydroxyvitamin D3 (7).
- Lithgoe, Basil,Waterhouse, Ian
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p. 1405 - 1406
(2007/10/02)
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