Hydrochloric Acid → Ethyl 2-bromoimidazo[5,1-b]thiazole-7-carboxylate

Temperature

1 °C

A suspension of sodium hydride (60% in mineral oil, 13.6 g, 368 mmol) in N,N-dimethylformamide (160 ml) was cooled to −10° C. or below under a nitrogen atmosphere. Ethyl isocyanoacetate (36.2 g, 320 mmol) was gradually added dropwise to the cooled suspension, and the mixture was stirred at −3 to 5° C. for 2 hr. This solution was cooled to −20° C. or below and was added dropwise to a solution of 2,5-dibromothiazole (38.8 g, 160 mmol) in N,N-dimethylformamide over a period of about 20 min, and the mixture was stirred at −5 to −20° C. for 2 hr. Water (8 ml) was added thereto to stop the reaction, and the reaction solution was added to 15 wt % brine (960 ml) under ice cooling. Subsequently, the mixture was adjusted to pH 6 to 7 by the addition of 1 M hydrochloric acid. Subsequently, common salt (102 g) was added thereto at the same temperature, and the mixture was stirred overnight. The resultant precipitate was collected by filtration, was washed with water (136 ml), and was dried under the reduced pressure to give ethyl 2-bromoimidazo[5,1-b]thiazole-7-carboxylate (40.4 g, yield 91.9%).

1. temperaturewas cooled to −10° C. or below under a nitrogen atmosphere
2. temperatureThis solution was cooled to −20° C. or below
3. stirringthe mixture was stirred at −5 to −20° C. for 2 hr
4. customthe reaction
5. stirringat the same temperature, and the mixture was stirred overnight
6. filtrationThe resultant precipitate was collected by filtration
7. washwas washed with water (136 ml)
8. customwas dried under the reduced pressure

ORD record

ord-04defe45e373492b970137fe32316a76

Source dataset

uspto-grants-2010_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07662841B2