反应详情

温度

60 °C

To a solution of the isomeric bromobenzo[b]thiophene (14.2 g, 66.5 mmol) from Step B above in N,N-dimethylformamide (130 mL) were added pyridine (7.5 mL) and copper(I) cyanide (7.75 g). The reaction mixture was heated under reflux for 20 hours. The reaction solution was then cooled to 60° C. and poured into a solution of ethylene diamine in water. The resultant mixture was stirred for 30 minutes and extracted with diethyl ether and ethyl acetate. The combined organic extract was washed with 1:1 brine/water, dried over sodium sulfate and concentrated under reduced pressure. The crude product obtained was purified by flash column:chromatography (95:5 to 91:9 hexanes/ethyl acetate) to give 4-cyanobenzo[b]thiophene (4.15 g, 39%) as a light yellow solid, and 6-cyanobenzo[b]thiophene (4.34 g, 41%) as a reddish oil: 1H NMR for 4-cyanobenzo[b]thiophene (CDCl3, 500 MHz) 8.10 (d, J=8.2 Hz, 1H), 7.74-7.70 (m, 2H), 7.62 (dd, J=5.5, 0.6 Hz, 1H), 7.43 (d, J=7.8 Hz, 1H); 1H NMR for 6-cyanobenzo[b]thiophene (CDCl3, 500 MHz) 8.22 (app s, 1H), 7.90 (d, J=8.3 Hz, 1H), 7.72 (d, J=5.4 Hz, 1H), 7.59 (d, J=8.3 Hz, 1H), 7.42 (dd, J=5.4, 0.5 Hz, 1H).

1. temperatureThe reaction mixture was heated
2. temperatureunder reflux for 20 hours
3. extractionextracted with diethyl ether and ethyl acetate
4. extractionThe combined organic extract
5. washwas washed with 1:1 brine/water
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe crude product obtained
9. customwas purified by flash column