3-Carbethoxy-2-piperidone → ethyl 3-[6-methoxy-5-(4-methyl-1H-imidazol-1-yl)pyridin-2-yl]-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridine-8-carboxylate

Participants

Reaction Steps

To a mixture of ethyl 2-oxopiperidine-3-carboxylate (3.5 g) in acetonitrile (100 mL) was added trimethyloxonium tetrafluoroborate (3.0 g) at room temperature, and the mixture was stirred at room temperature for 2 hr. 6-Methoxy-5-(4-methyl-1H-imidazol-1-yl)pyridine-2-carbohydrazide (5.0 g) was added to the reaction mixture at room temperature, and the solvent was evaporated under reduced pressure. Methanol (100 mL) was added to the residue at room temperature, and the mixture was stirred for 2 hr under reflux. The solvent in the reaction mixture was evaporated under reduced pressure, acetonitrile (100 mL) was added to the residue at room temperature, and the mixture was stirred at 80° C. overnight. The solvent in the reaction mixture was evaporated under reduced pressure, the residue was diluted with ethyl acetate and saturated aqueous sodium hydrogen carbonate solution, the mixture was washed with saturated brine and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue of another lot synthesized similarly was combined, and the mixture was purified by silica gel column chromatography (methanol/ethyl acetate) to give the title compound (3.1 g).

Provenance & Evidence