Hydrochloric Acid → Ethyl cis(+/-)-2-(4-{[(4-chloro-5-ethyl-1H-imidazol-2-yl)carbonyl]amino}-3-methoxypiperidin-1-yl)-1,3-benzothiazole-7-carboxylate

Participants

Reaction Steps

tert-Butyl cis(±)-4-{[(4-chloro-5-ethyl-1H-imidazol-2-yl)carbonyl]amino}-3-methoxypiperidine-1-carboxylate obtained in Example (1g) (117 mg, 0.30 mmol) was dissolved in methanol (2 mL). A 4 N hydrochloric acid/ethyl acetate solution (5 mL) was added, and the mixture was stirred at room temperature for one hour. Following concentration under reduced pressure, the residue was dissolved in DMF (3 mL). Diisopropylethylamine (0.32 mL, 1.84 mmol) and ethyl 2-bromo-1,3-benzothiazole-7-carboxylate obtained in Example (1f) (87 mg, 0.30 mmol) were added, and the mixture was stirred at 70° C. for two hours. Dilute hydrochloric acid was added to the reaction solution, followed by extraction with ethyl acetate. The organic layer was washed with water, saturated aqueous sodium bicarbonate solution and brine, and dried over anhydrous sodium sulfate. Following concentration under reduced pressure, the residue was purified by silica gel column chromatography (elution solvent: hexane/ethyl acetate=5/1, ethyl acetate) to obtain 97 mg of the title compound as a pale yellow solid (65%).

Provenance & Evidence