反应详情

31.5 g of 4-ethoxy-1-(2-furyl)methyl-1H-pyrazolo[3,4-b]-pyridine-5-carboxylic acid ethyl ester (0.1 mol) and 20 g of selenium dioxide (0.18 mol) are suspended in 100 ml diethyleneglycol dimethylether. The mixture is heated with stirring at 160° and a few drops of water are added. The temperature is held steady for 1.5 hours. After cooling, 100 ml of water is added and the mixture is neutralized with a dilute solution of aqueous ammonia. Yellow crystals are formed, which yield on recrystallization from methanol 15.8 g of 4-ethoxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester (67%), m.p. 180°.

1. temperatureThe mixture is heated
2. temperatureAfter cooling
3. customYellow crystals are formed