反应详情

A mixture of 5-hydroxy-pyrazine-2-carboxylic acid methyl ester (Preparation 40, 50 g, 324 mmol) and POCl3 (500 mL, 5.36 mol) was heated under reflux for 1.5 hours and then poured onto ice. The resulting mixture was extracted with ether (4×500 mL). The organic layers were concentrated in vacuo, and the residue was recrystallised from toluene to give the title compound (30.8 g) in a 55% yield.

1. temperaturewas heated
2. temperatureunder reflux for 1.5 hours
3. additionpoured onto ice
4. extractionThe resulting mixture was extracted with ether (4×500 mL)
5. concentrationThe organic layers were concentrated in vacuo
6. customthe residue was recrystallised from toluene