反应详情

40 g. of 6-ethoxy-1-ethyl-1H-pyrazolo[3,4-b]pyrazine-5-carboxylic acid (0.17 mol.) and 300 ml. of thionyl chloride are refluxed for 21/2 hours. After removal of the excess thionyl chloride under vacuum, the 6-ethoxy-1-ethyl-1 H- pyrazolo[3,4-b]-pyrazine-5-carbonyl chloride is treated with hexane, filtered off and then dried at 60°, yield 41.5 g. (96%), m.p. 86°-87°.

1. customAfter removal of the excess thionyl chloride under vacuum
2. additionthe 6-ethoxy-1-ethyl-1 H- pyrazolo[3,4-b]-pyrazine-5-carbonyl chloride is treated with hexane
3. filtrationfiltered off
4. customdried at 60°