名称:
Synthesis of polyhydroxysterols (I): synthesis of 24-methylenecholest-4-en-3β,6β-diol, a cytotoxic natural hydroxylated sterol
摘要:
Starting from stigmasterol (2), 24-methylenecholest-4-en-3 beta ,6 beta -diol (1), a cytotoxic natural dihydroxylated sterol, was synthesized via 10 steps in 20% overall yield. The introduction of a side-chain of sterol was achieved by solid-liquid phase-transfer Wittig reaction using (3-methyl-2-oxo)butyltriphenylarsonium bromide (12) and K2CO3. Construction of the steroidal nucleus was finished by the addition of 3 beta -acetoxycholest-5,6-en-24-one (7) with NBA in dioxane under ambient temperature and by the elimination of 3 beta, 6 beta -diacetoxy-5a-bromocholestane-24-one (9). The spectral data of the synthetic product (1) are completely consistent with those of the natural compound (1). (C) 2001 Elsevier Science Inc. All rights reserved.