反应详情

A mixture of 3-amino-2-thiophenecarboxylic acid (8 g, 49 mmol), ethyl 4-fluorobenzoylacetate (9.6 g, 49 mmol), and p-toluenesulfonic acid monohydrate (0.2 g, 1 mmol) in toluene (100 mL) is refluxed for about 20 hours in a flask equipped with a Dean-Stark water trap. The mixture is cooled to room temperature. The precipitate is filtered and washed with diethyl ether. The solid is dissolved in diphenyl ether (80 mL) and heated at 240° C. for about 2 hours. The reaction solution is then cooled to room temperature, diethyl ether is added and the precipitate is filtered and washed with diethyl ether to give 5-(4-fluorophenyl)-thieno[3,2-b]pyridin-7-ol (2 g, 17% yield) as brown crystalline needles, m.p. 316-318 ° C.

1. temperatureis refluxed for about 20 hours in a flask
2. filtrationThe precipitate is filtered
3. washwashed with diethyl ether
4. dissolutionThe solid is dissolved in diphenyl ether (80 mL)
5. temperatureheated at 240° C. for about 2 hours
6. temperatureThe reaction solution is then cooled to room temperature
7. additiondiethyl ether is added
8. filtrationthe precipitate is filtered
9. washwashed with diethyl ether