Cycloaddition of Cross-Conjugated Trienes to Halogenated Quinones
作者:Michel Couturier、Paul Brassard
DOI:10.1055/s-1994-25553
日期:——
The chemoselectivity of [4 + 2] cycloadditions involving electronrich cross-conjugated trienes and halogenated quinones has been examined. The approach provides improved preparations of 6-acetyl-2,3,7-trihydroxyjuglone, solorinic and norsolorinic acids, and averythrin. It also confirms the structure proposed for haematommone and 3,8-dihydroxy-4-methoxy-2-methoxycarbonyl-1-methyl-anthraquinone but invalidates that of sopheranin.
Three minor new anthraquinones were isolated from the bulb of Eleutherine americana Merr. et Heyne. Their structures were elucidated as methyl ethers of 3, 4, 8-trihydroxy-1-methyl-anthra-9, 10-quinone-2-carboxylic acid methyl ester 4-6 by spectral analyses including long-range selective proton decoupling (LSPD) experiments in 13C-NMR.
从 Eleutherine americana Merr. et Heyne 的鳞茎中分离出三种次要的新蒽醌。通过光谱分析,包括 13C-NMR 长程选择性质子解偶联(LSPD)实验,阐明了它们的结构为 3, 4, 8-三羟基-1-甲基-蒽-9, 10-醌-2-羧酸甲酯 4-6 的甲醚。