反应详情

A solution of 2-bromo-5-cyanothiophene (4.9 g), 4-methoxyphenyl boronic acid (4.7 g), 2M aqueous sodium carbonate solution (80 cm3), tetrakis(triphenylphosphine)palladium (0) (0.4 g) and dimethoxyethane (80 cm3) was heated under reflux for 6 h under an atmosphere of nitrogen. 20% Hydrochloric acid (200 cm3) was added and the resultant mixture extracted with diethyl ether (5×100 cm3). The combined organic layers were washed with 20% hydrochloric acid (1×100 cm3), brine (2×100 cm3) and then dried (MgSO4), filtered and evaporated down. The residue was purified by column chromatography on silica gel using a 9:1 hexane/ethyl acetate mixture as eluent and recrystallisation from ethanol to yield 4.5 g of 2-cyano-5-(4-methoxyphenyl)thiophene, K 58-60° C., I.

1. temperatureunder reflux for 6 h under an atmosphere of nitrogen
2. extractionthe resultant mixture extracted with diethyl ether (5×100 cm3)
3. washThe combined organic layers were washed with 20% hydrochloric acid (1×100 cm3), brine (2×100 cm3)
4. dry with materialdried (MgSO4)
5. filtrationfiltered
6. customevaporated down
7. customThe residue was purified by column chromatography on silica gel using a 9:1 hexane/ethyl acetate mixture as eluent
8. customrecrystallisation from ethanol