Triphosgene → 8-bromo-7-(4-chlorophenyl)-5-methyl-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one

Participants

Reaction Steps

To a solution of triphosgene (225 mg, 0.75 mmol) in anhydrous THF (2.5 mL) at 60° C. was added 3-bromo-4-(4-chlorophenyl)-2-hydrazinyl-6-methylpyridine (80 mg, 0.256 mmol) in small portions over 5 min. The resulting suspension was refluxed for 30 min. After cooling to room temperature, the reaction mixture was concentrated under reduced pressure to remove most of the THF. Water (5 mL) was added carefully to the remaining solution to destroy the excess triphosgene. The resulting aqueous suspension was stirred at room temperature for 30 min, then filtered. The collected solid was washed with water (5 mL×2), the hexanes, and dried in a 45° C. vacuum oven for 3 h to afford 70 mg (84%) of the title compound as a yellow solid. HPLC/MS: retention time=3.38 min, [M+H]+=338.0.

Provenance & Evidence