反应详情

250 g of [[[1-(2-furyl)methyl-5-pyrazolyl]amino]methylene]-malonic acid diethyl ester (0.75 mol) is dissolved in 1 liter of diphenyl ether and heated to 240° for 2 hours. The ethanol formed is continuously distilled off. The solvent is removed in vacuo. The 4-hydroxy-1-(2-furyl)methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester remains and is recrystallized from methanol, yield 248 g (86%), m.p. 103°-106°.

1. temperatureheated to 240° for 2 hours
2. distillationis continuously distilled off
3. customThe solvent is removed in vacuo
4. customis recrystallized from methanol, yield 248 g (86%), m.p. 103°-106°