反应详情

300 g of 4-hydroxy-1-(2-furyl)methyl-1H-pyrazolo[3,4-b]-pyridine-5-carboxylic acid ethyl ester (1.05 mol) is dissolved in 1 liter of dimethylformamide. 210 g of potassium carbonate (1.5 mol) and 233 g of ethyl iodide are added. The mixture is heated at 60° with continuous stirring for 10 hours. The excess potassium carbonate is filtered off. On addition of 500 ml of water, 4-ethoxy-1-(2-furyl)methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester precipitates and is recrystallized from methanol, yield 280 g (85%), m.p. 93°-96°.

1. temperatureThe mixture is heated at 60°
2. filtrationThe excess potassium carbonate is filtered off
3. additionOn addition of 500 ml of water, 4-ethoxy-1-(2-furyl)methyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester
4. customprecipitates
5. customis recrystallized from methanol, yield 280 g (85%), m.p. 93°-96°