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

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Reaction Steps

1-(3,4,5-trimethoxyphenyl)-1,2-ethanedithiol (39) (0.148 g,0.57 mmole), 3,5-dimethoxy-4-methylthiobenzaldehyde (48) (FIG. 23) (0.11 g, 0.519 mmole) and 0.052 g of pyridinium para-toluenesulfonate was added to 40 ml dry benzene and refluxed with Dean-Stark removal of the benzene- water azeotrope for 48 hours. The benzene was removed in vacuo, and the remaining oil redissolved in dichloromethane. The organic layer was washed with 3×30 ml H2O and 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 (0.151 g, 64%). The trans isomer was isolated after two recrytallizations of this mixture from methanol.

Provenance & Evidence