An improved synthesis of the diastereomers of 1alpha,25-dihydroxyvitamin D3 (1) was accomplished utilizing our practical route to the A-ring synthon. We applied this procedure to synthesize for the first time all possible A-ring diastereomers of 20-epi-1alpha,25-dihydroxyvitamin D3 (2). Ten-step conversion of 1-(4-methoxyphenoxy)but-3-ene (6), including enantiomeric introduction of the C-3 hydroxyl
Design and Efficient Synthesis of 2α-(ω-Hydroxyalkoxy)-1α,25-dihydroxyvitamin D<sub>3</sub> Analogues, Including 2-<i>e</i><i>pi</i>-ED-71 and Their 20-Epimers with HL-60 Cell Differentiation Activity
A concise and efficient synthetic approach to 2α-(ω-hydroxyalkoxy)-1α,25-dihydroxyvitamin D3 (4a−c), including 2-epi-ED-71, was developed starting from d-glucose as a chiral template for the construction of the 2α-modified A-ring precursors (11a−c). It was found that the best ligand for the bovine thymus vitamin D receptor (VDR) in this series is 4b, which has 1.8 times greater binding affinity for
Systematic studies on synthesis, structural elucidation, and biological evaluation of A-ring diastereomers of 2-methyl-1α,25-dihydroxyvitamin D3 and 20-epi-2-methyl-1α,25-dihydroxyvitamin D3
diastereomers of 2-methyl-1alpha,25-dihydroxyvitamin D(3) (2) and 20-epi-2-methyl-1alpha,25-dihydroxyvitamin D(3) (3) were synthesized by palladium-catalyzed coupling reaction of A-ring 'enyne' synthons with CD-ring portions. The A-ring synthons were rationally synthesized via a novel and practical route, starting with methyl (R)-(+)- and (S)-(-)-3-hydroxy-2-methyl-propionate, in good yields. X-ray
The object of the present invention is to synthesize vitamin D derivatives in which the
3
-position is substituted with methyl and the steric configuration at the
20
-position is epimerized.
The present invention provides vitamin D derivatives of Formula (
1
):
1
wherein R is straight or branched alkyl optionally substituted with hydroxy.
We found a concise route to the Trost A-ring precursor enyne for synthesizing 2alpha-alkylated 1alpha,25-dihydroxyvitamin D-3 (1) from D-glucose. The enynes were coupled with the 20-epi-CD ring part to study the effect of the double modification of 2alpha-substitution and 20-epimerization upon biological activities of 1. The novel three analogues of 2alpha-alkyl- and four analogues of 2alpha-(omega-hydroxyalkyl)-20-epi-1alpha,25-dihydroxyvitamin D-3 (5b-d and 6a-d) showed higher binding affinity for vitamin D receptor (VDR) and more potent activity in induction of HL-60 cell differentiation than those of the natural hormone 1. (C) 2003 Elsevier Ltd. All rights reserved.