Diethyl Oxalate → Ethyl 8-chloro-6-(trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyridine-3-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of 3-chloro-2-hydrazinyl-5-(trifluoromethyl)pyridine (600 mg), diethyl oxalate (1.15 mL) and 2M hydrogen chloride ethanol solution (9 mL) was heated with microwave irradiation at 140° C. for 2 hr. The reaction mixture was allowed to be cooled to room temperature, and the solvent was evaporated under reduced pressure. The residue was neutralized with saturated aqueous sodium hydrogen carbonate solution, and the mixture was extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate/hexane) to give the title compound (290 mg).

Provenance & Evidence