反应详情

Preparation is according to the method disclosed in U.S. Pat. No. 4,028,373. A solution of 0.5 g. of 4-(aminosulfonyl)-3-thiophenecarboxylic acid methyl ester in 20 ml. of 10% aqueous sodium hydroxide is allowed to sit at room temperature for 3 days. The solution is acidified with concentrated hydrochloric acid. The precipitate which forms is collected to give 0.35 g. of product. A small amount is recrystallized twice from ethyl acetate (petroleum ether is added to the cloudy point to initiate precipitation) to give the analytical sample, m.p. 222°-224° C.

1. customPreparation
2. customThe precipitate which forms is collected
3. customto give 0.35 g
4. customA small amount is recrystallized twice from ethyl acetate (petroleum ether
5. additionis added to the cloudy point
6. customprecipitation)
7. customto give the analytical sample, m.p. 222°-224° C.