反应详情

1-(3,4,5-trimethoxyphenyl)-1,2-ethanedithiol (39) (FIG. 19) (1.404 g,5.40 mmole), 3,4-dimethoxy-5-iodobenzaldehyde (41) (FIG. 22) (1.30 g, 4.45 mmole) and 0.542 g of pyridinium para-toluenesulfonate was added to 50 ml dry benzene and refluxed with Dean-Stark removal of the benzene- water azeotrope for 12 hours. The benzene was removed in vacuo, and the remaining oil redissolved in ethyl acetate. The organic layer was washed with 10% NaHCO3 and H2O. The organic layer was dried over MgSO4, and evaporated in vacuo to an oil which was purified by flash column chromatography with 2:1 hex/ethyl acetate as eluent. The product mixture contains a 1.0/1.0 cis/trans ratio (2.38 g, 100%). The trans isomer can be isolated by recrystallization from methanol.

1. customThe benzene was removed in vacuo
2. dissolutionthe remaining oil redissolved in ethyl acetate
3. washThe organic layer was washed with 10% NaHCO3 and H2O
4. dry with materialThe organic layer was dried over MgSO4
5. customevaporated in vacuo to an oil which
6. customwas purified by flash column chromatography with 2:1 hex/ethyl acetate as eluent
7. customThe trans isomer can be isolated by recrystallization from methanol