Ethyl 3-methyl-imidazo[2,1-b]thiazole 4-carboxylate

96-50-4

609-15-4

57626-37-6

The reaction was carried out with 2-aminothiazole (3.00 g, 29.99 mmol) and ethyl 2-chloroacetoacetate (4.96 mL, 35.99 mmol) in 1,2-dimethoxyethane (30 mL) at 90 °C for 6 hours. Upon completion of the reaction, the reaction mixture was concentrated under reduced pressure and diluted with ethyl acetate (80 mL), followed by washing the organic layer with water (3 x 30 mL). The organic layer was separated and dried with anhydrous sodium sulfate and concentrated in vacuum to obtain the crude product. The crude product was purified by column chromatography using 20% ethyl acetate/hexane as eluent to give ethyl 6-methylimidazo[2,1-b]thiazole-5-carboxylate (2a) (5.20 g, 82% yield) as an off-white solid. The molecular weight of the product was confirmed to be 211 [M + H]+ by electrospray ionization mass spectrometry (ESIMS), followed by the next step of the reaction.