Benzene → trans 2-(3,4-Dimethoxy-5-iodophenyl)-4-(3,4,5-trimethoxyphenyl)-1,3-dithiolane

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Reaction Steps

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.

Provenance & Evidence