261905-71-9

Upstream product

• 261905-69-5 (S)-1-(4-methoxyphenoxy)hex-5-yn-3-ol 
• 261905-70-8 (S)-3-[(benzyloxymethyl)oxy]-1-(4-methoxyphenoxy)hex-5-yne 

Downstream Products

• 261905-76-4 (3R,5S)-5-[(benzyloxymethyl)oxy]oct-1-en-7-yn-3-ol 
• 261905-77-5 (3S,5S)-5-[(benzyloxymethyl)oxy]oct-1-en-7-yn-3-ol 
• 96614-28-7 (5Z,7E)-(1R,3S,20R)-9,10-seco-5,7,10⁽¹⁹⁾-cholestatriene-1,3,25-triol 

Relevant academic research and scientific papers

Efficient synthesis and biological evaluation of all A-ring diastereomers of 1α,25-dihydroxyvitamin D3 and its 20-epimer

An improved synthesis of the diastereomers of 1α,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-1α,25-dihydroxyvitamin D3 (2). Ten-step conversion of 1-(4-methoxyphenoxy)but-3-ene (6), including enantiomeric introduction of the C-3 hydroxyl group to the olefin by the Sharpless asymmetric dihydroxylation, provided all four possible stereoisomers of A- ring enynes (3), i.e., (3R,5R)-, (3R,5S)-, (3S,5R)- and (3S,5S)-bis[(tert- butyldimethylsilyl)oxy]oct-1-en-7-yne, in good overall yield. Palladium- catalyzed cross-coupling of the A-ring synthon with the 20-epi CD-ring portion (5), (E)-(20S)-de-A,B-8-(bromomethylene)cholestan-25-ol, followed by deprotection, afforded the requisite diastereomers of 20-epi-1α,25- dihydroxyvitamin D3 (2). The biological profiles of the synthesized stereoisomers were assessed in terms of affinities for vitamin D receptor (VDR) and vitamin D binding protein (DBP), HL-60 cell differentiation- inducing activity and in vivo calcium-regulating potency in comparison with the natural hormone. (C) 2000 Elsevier Science Ltd.

A novel and practical route to A-ring enyne synthon for 1α,25-dihydroxyvitamin D3 analogs: Synthesis of A-ring diastereomert of 1α,25-dihydroxyvitamin D3 and 2-methyl-1,25-dihydroxyvitamin D3

A novel and practical route to the A-ring enyne synthon (2), which can be versatile far a variety of A-ring analogs of 1α,25-dihydroxyvitamin D3 (1), was developed. This novel method led to an improved synthesis of the A-ring diastereomers of 1, the compounds 13-15, and synthesis of the new analogs, 2-methyl-1,25-dihydroxyvitamin D3 (4) with its all possible diastereomers. The biological evaluation of the 2-methyl analogs showed the ααβ-isomer to be more potent than 1.