Di-2-pyridyl carbonate is used as a coupling agent in the esterification of carboxylic acids (e.g. 3-Cyclohexenylcarboxylic acid [C988195]). Di-2-pyridyl carbonate is also used as a reagent to synthesize active carbonates (e.g. benzyl 2-pyridyl carbonate) and carbamates (e.g. 3-Pyridyl diethylcarbamate [P992950]).
A solution of phosgene (2.5 m in toluene, 2 mL, 5.0 mmol) was diluted with dichloromethane (8 mL) and then a solution of 2-pyridinol 853 (950 mg, 10 mmol) and triethylamine (1.214 g, 10.2 mmol) in dichloromethane (20 mL) was added at 0 ℃. The reaction mixture was stirred at 0℃ for 1 h, then washed with cold 5% NaHCO3 solution (20 mL) and cold saturated brine (20 mL), dried over MgSO4, and filtered. The filtrate was concentrated to dryness to give di-2-pyridyl carbonate, DPC, 725 (972 mg) in 90% yield. It was recrystallized from dichloromethane/petroleum ether (811 mg, 75%); mp 84–86℃. DPC has also been produced as its hydrochloride salt 877, in a more facile procedure on a larger scale, in 97% yield.
