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

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Reaction Conditions

Reaction Steps

cis(±)-4-Chloro-N-{3-(2,2-difluoroethoxy)-1-(trifluoroacetyl)piperidin-4-yl}-5-ethyl-1H-imidazole-2-carboxamide obtained in Example (121f) (144 mg, 0.33 mmol) was dissolved in methanol (4 mL). A 2 N aqueous lithium hydroxide solution (0.4 mL) was added, and the mixture was stirred at 40° C. for 40 minutes. The pH was adjusted to 4 by adding a 1 N aqueous hydrochloric acid solution, and the solvent was evaporated under reduced pressure. The residue was dissolved in DMA (5 mL). Diisopropylethylamine (130 mg, 1 mmol) and ethyl 2-bromo-1,3-thiazole-5-carboxylate (155 mg, 0.66 mmol) were added, and the mixture was stirred at 75° C. for one hour. Dilution with ethyl acetate, washing with water and brine, drying over anhydrous magnesium sulfate, and concentration under reduced pressure gave a residue, which was purified by silica gel column chromatography (elution solvent: ethyl acetate/hexane=1/4, 2/3, 3/2, 4/1) to obtain 0.12 g of the title compound as a colorless amorphous solid (74%).

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