81203-50-1Relevant articles and documents
Stereoselective Synthesis of Four Calcitriol Lactone Diastereomers at C23 and C25
Nagata, Akiko,Akagi, Yusuke,Masoud, Shadi Sedghi,Yamanaka, Masahiro,Kittaka, Atsushi,Uesugi, Motonari,Odagi, Minami,Nagasawa, Kazuo
, p. 7630 - 7641 (2019/05/16)
(23S,25R)-Calcitriol lactone is a major metabolite of vitamin D3, but its synthesis has been far less well investigated than that of 1α,25(OH)2 vitamin D3, the active form of vitamin D3, even though the lactone
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.