Ethyl 2-amino-6-chloropyridine-4-carboxylate → Ethyl 5-chloro-3-{(4,4-difluorocyclohexyl)methyl}-2-(trifluoromethyl)imidazo[1,2-a]pyridine-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

Ethyl 2-amino-6-chloroisonicotinate (510 mg, 2.54 mmol) obtained in step 1 was suspended in n-butanol (5.08 mL), and the suspension was stirred overnight at 130° C. after adding 3-bromo-4-(4,4-difluorocyclohexyl)-1,1,1-trifluorobutan-2-one (821 mg, 2.54 mmol) obtained in step 2 of Example 36, and molecular sieve 4A (510 mg). The reaction mixture was allowed to cool to room temperature, and, after adding a sodium hydrogen carbonate aqueous solution, the mixture was filtered through Celite (registered trademark), and extracted with ethyl acetate. The organic layer was washed with water and saturated brine, and dried over anhydrous sodium sulfate. The solvent was then evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=9/1→2/1), amino silica gel column chromatography (hexane/ethyl acetate=20/1→9/1), and preparative thin-layer chromatography (hexane/ethyl acetate=9/1) to give ethyl 5-chloro-3-{(4,4-difluorocyclohexyl)methyl}-2-(trifluoromethyl)imidazo[1,2-a]pyridine-7-carboxylate (62.0 mg, yield 5.7%).

Provenance & Evidence