Triethylamine → Methyl 2,6-Bis(trifluoromethyl)-4-(diphenylaminocarbonyloxy)-3-pyridinecarboxylate

To a solution of 2 g (0.0069 mol) of methyl 2,6-bis(trifluoromethyl)-4-hydroxy-3-pyridinecarboxylate (example 4 of U.S. Pat. No. 4,655,816) in 20 mL of acetonitrile was added 0.7 g of triethylamine. A solution of 1.6 g (0.0069 mol) of diphenylcarbamyl chloride in 20 mL of acetonitrile was added to the above mixture and the resulting mixture was stirred at room temperature over the weekend. The precipitate formed was filtered off and the filtrate was concentrated in vacuo. The residue was slurried with ether. The insoluble material was filtered. The ether filtrate was concentrated and the residue was recrystallized from cyclohexane to give a white solid, mp 114-116° C.