反应详情

Methyl isocyanoacetate (0.63 ml, 6.9 mmol) was gradually added dropwise to a suspension of sodium hydride (60% in mineral oil, 346 mg, 8.6 mmol) in N,N-dimethylformamide (5 ml) in an argon atmosphere under ice cooling, and the mixture was stirred at the same temperature for 2 hr. This solution was added dropwise to a solution of 2,5-dibromothiazole (1.0 g, 4.1 mmol) in tetrahydrofuran (10 ml) cooled to −20° C. (brine/ice water) through a cannula over a period of 15 min, and, while allowing the temperature to rise to about 0° C., the mixture was stirred for 2 hr. After the completion of the reaction, saturated brine was added thereto, and the mixture was extracted with dichloromethane (20 ml×5). The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed by distillation under the reduced pressure. The residue was washed with ethyl acetate to give methyl 2-bromoimidazo[5,1-b]thiazole-7-carboxylate (910 mg, 85%) as a white solid.

1. customto rise to about 0° C.
2. stirringthe mixture was stirred for 2 hr
3. additionwas added
4. extractionthe mixture was extracted with dichloromethane (20 ml×5)
5. dry with materialThe organic layer was dried over anhydrous sodium sulfate
6. customthe solvent was removed by distillation under the reduced pressure
7. washThe residue was washed with ethyl acetate