Ammonia → 6-[m-(1,3-Dimethylpyrazole-5-carboxamido)phenyl]-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole

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Reaction Steps

To 6-(m-aminophenyl)-2,3,5,6-tetrahydroimidazo[2,1-b]thiazole (2.4 g, 11 mmol) in dry dichloromethane (30 ml) under nitrogen was added trimethylaluminium (4.8 ml; 25% in hexane). After 20 mins at room temperature 1,3-dimethylpyrazole-5-carboxylic acid ethyl ester (1.8 g, 11 mmol) in dry dichloromethane (1 ml) was added and the mixture heated under reflux for 24 hours. Hydrochloric acid (20 ml; 2 N aqueous) was added slowly, the resulting mixture basified with aqueous ammonia solution (5 N; 100 ml) and extracted with chloroform (3×200 ml) which after drying (MgSO4) and concentrating in vacuo afforded an oil. Separation of the oil on alumina eluting with chloroform gave the amide (1.28 g; 34%).

Provenance & Evidence