反应详情

A suspension of ethyl 2-bromoimidazo[5,1-b] thiazole-7-carboxylate (49.5 g, 200 mmol) in methanol (720 ml) was cooled in a brine/ice water bath. A 2.7 M aqueous solution (720 ml) of sodium hydroxide was added to this suspension, and the mixture was stirred at room temperature for about 15 hr. After the completion of the reaction, methanol was removed by distillation under the reduced pressure for concentration, and the concentrate was cooled in a brine/ice water bath. Concentrated hydrochloric acid (164 ml) was added to this concentrate, and the mixture was adjusted to pH 5 and was stirred at room temperature overnight. The resultant precipitate was collected by filtration. The precipitate was then washed with water (60 ml) and was dried under the reduced pressure to give 2-bromoimidazo[5,1-b]thiazole-7-carboxylic acid (46.5 g, yield 94.0%) as a white solid.

1. temperaturewas cooled in a brine/ice water bath
2. customwas removed by distillation under the reduced pressure for concentration
3. temperaturethe concentrate was cooled in a brine/ice water bath
4. additionConcentrated hydrochloric acid (164 ml) was added to this concentrate
5. stirringwas stirred at room temperature overnight
6. filtrationThe resultant precipitate was collected by filtration
7. washThe precipitate was then washed with water (60 ml)
8. customwas dried under the reduced pressure