Methanol → Methyl pyrazinoate

Temperature

61 °C

106.6 g of thionyl chloride was added dropwise over 1 hour at 4° to 6° C. to 1200 ml of methanol under argon. 100.1 g of pyrazinecarboxylic acid was added at 9° C. and the mixture was heated for 2 hours at 61° C., with 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 50 to 120 mbar and a bath temperature of 45° C., and the residue was extracted three times with dichloromethane (400 ml, 100 ml, 100 ml). Concentration of the organic phase provided 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). Other data concerning the title compound was:

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

ORD record

ord-2b437b71191049309b3302e2d56ddfa1

Source dataset

uspto-grants-1999_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05945534