New 1α,25-dihydroxy vitamin D2 derivatives (22,23-dihydro-1α,25-dihydroxyvitamin D2 (2a)) and its 24R-epimer (2b), were synthesized by two procedures. 22-Oxo-5α,8α-(4-phenyl-3,5-dioxo-1,2,4-triazolidine-1,2-diyl)-23,24-dinor-6-cholene-1α,3β-diyl diacetate (8), obtainable readily from ergosterol, was converted to 22-phenylsulfonyl-5α,8α-(4-phenyl-3,5-dioxo-1,2,4-triazolidine-1,2-diyl)-1α,3β-bis(tet
新的 1α,25-二羟基
维生素 D2 衍
生物(22,23-二氢-1α,25-二羟基
维生素 D2 (2a))及其 24R-差向异构体 (2b) 通过两种方法合成。22-Oxo-5α,8α-(4-phenyl-3,5-dioxo-1,2,4-triazolidine-1,2-diyl)-23,24-dinor-6-cholene-1α,3β-diyl diacetate (8) 可容易地从
麦角甾醇中获得,转化为 22-苯基磺酰基-5α,8α-(4-苯基-3,5-二氧代-
1,2,4-三唑烷-1,2-二基)-1α,3β-双(
四氢吡喃氧基)-23,24-dinor-6-cholene (14) 或 22-iodo-5α,8α-(4-phenyl-3,5-dioxo-1,2,4-triazolidine-1,2-diyl )-1α,3β-双(
四氢吡喃氧基)-23,24-dinor-6-cholene (16)。C-22