125315-55-1Relevant articles and documents
Facile Stereoselective Synthesis of (23S,25R)-1α,25-Dihydroxyvitamin D3 26,23-Lactone, a Major Metabolite of 1α,25-Dihydroxyvitamin D3
Yamamoto, Keiko,Shimizu, Masato,Yamada, Sachiko,Iwata, Suguru,Hoshino, Osamu
, p. 33 - 39 (2007/10/02)
(23S,25R)-1α,25-Dihydroxyvitamin D3 26,23-lactone (1a), a major metabolite of 1α,25-dihydroxyvitamin D3 2, was synthesized efficiently and stereoselectively from 1α-hydroxydehydroepiandrosterone (3).The 17-oxosteroid 3 was first converted to C(22)-steroid aldehyde 9 with the natural stereochemistry at C(17) and C(20) using a stereoselective ene reaction as the key step.Then it was combined with the chiral C5 sulfone 4 having the correct stereochemistry for the lactone in 1a.Sulfone 4 was readily obtained from commercially available (R)-citramalic acid.The side-chain lactone with the natural stereochemistry at C(23) was constructed with high stereoselectivity (84percent) by iodo lactonization of the Δ22-26-carboxylic acid 16b under kinetically controlled conditions in the presence of γ-collidine.The stereoselectivity of the iodo lactonization of steroidal Δ22-25-hydroxy-26-carboxylic acids 16b, 24, and 25 was studied in detail, and a mechanism is proposed in which the configuration at C(25) and an added pyridine base play an important role.
Syntheses of Cholesta-5,7-diene-3β,25-diol and Cholesta-5,7-diene-1α,3β,25-triol
Tachibana, Yoji,Yokoyama, Shinji,Tsuji, Masahiro
, p. 2599 - 2603 (2007/10/02)
Adducts of 3β-acetoxy- and 1α,3β-diacetoxy-23,24-dinorchola-5,7-dien-22-al (7 and 14) with 4-phenyl-3H-1,2,4-triazole-3,5-dione prepared by the ozonolysis of the corresponding adducts of ergosteryl acetate and 1α-acetoxyergosteryl acetate were transformed