Methanol → Methyl pyrazinoate

Temperature

61 °C

106.6 g of thionyl chloride was added dropwise over 1 hour to 1200 ml of methanol under argon at 4° to 6° C. 100.1 g of pyrazinecarboxylic acid was added at 9° C. and the mixture was heated at 61° C. for 2 hours, the acid passing completely into solution. After cooling to room temperature, a solution of 145 g of sodium hydrogen carbonate in 1.4 l of water was added slowly. The methanol was distilled off on a rotary evaporator at a bath temperature of 45° C. and at 50 to 120 mbar and the residue was extracted three times with dichloromethane (400 ml, 100 ml, 100 ml). Concentration of the organic phase gave 83.15 g of crude product, which was recrystallized from ca. 250 g of diisopropyl ether. The yield of the title compound was 70.6 g plus 10.28 g from the mother liquor (total 72.5 percent). Further data concerning the title compound was:

1. temperatureAfter cooling to room temperature
2. distillationThe methanol was distilled off on a rotary evaporator at a bath temperature of 45° C.
3. extractionat 50 to 120 mbar and the residue was extracted three times with dichloromethane (400 ml, 100 ml, 100 ml)

ORD record

ord-b43f638a4a254309b22e2d8f11a471cf

Source dataset

uspto-grants-1999_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05886181