Hydrochloric Acid → 2-(4,4-Difluoropiperidin-1-yl)benzo[d]thiazole-6-carboxylic acid

Participants

Reaction Steps

A mixture of ethyl 2-bromo-benzo[d]thiazole-6-carboxylate 49a (1.75 mmol, 500 mg), 4,4-difluoropiperidine 49b (1.92 mmol, 303 mg), and Cs2CO3 (5.24 mmol, 1.71 g) in 15 mL of CH3CN was refluxed overnight. The suspension was cooled to room temperature and 15 mL of water was added to the mixture (containing ethyl 2-(4,4-difluoropiperidin-1-yl)benzo[d]thiazole-6-carboxylate 49c). The reaction mixture was heated at 60° C. for 18 h. After cooling, the mixture was acidified using 3N aqueous HCl and the resulting precipitate was filtered to give 575 mg (99%) of 49d. MS m/z (M+H+) 299.1.

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