反应详情

4.1 g of 4-hydroxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester (0.02 mol), 5.6 g of potassium carbonate (0.04 mol) and 3.5 g of ethyl iodide (0.022 mol) are heated in 30 ml of dimethylformamide with stirring for 10 hours at 60°. After this time, the excess potassium carbonate is filtered off and 30 ml of water is added. 4-Ethoxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester precipitates and is recrystallized from methanol, yield 2 g (42.5%), m.p. 180°.

1. filtrationAfter this time, the excess potassium carbonate is filtered off
2. addition30 ml of water is added
3. custom4-Ethoxy-1H-pyrazolo[3,4-b]pyridine-5-carboxylic acid ethyl ester precipitates
4. customis recrystallized from methanol, yield 2 g (42.5%), m.p. 180°