反应详情

Ethyl 7-chloro-1H pyrazolo[4,3-b]pyridine-6-carboxylate (4.5 g, 0.02 mole) and dimethyl formamide demethylacetal2 (10 ml, 0.04 mole) in dry toluene (200 ml) were heated together under reflux for 1 h. The solvent and excess of reagent were distilled off under reduced pressure to give a brown oil containing two isomers. The 1-methyl3 and 2-methyl isomers were separated by column chromatography on silica gel with ethyl acetate as eluant to give the title compound as a white crystalline solid m.p. 118°-120° C.

1. temperatureunder reflux for 1 h
2. distillationThe solvent and excess of reagent were distilled off under reduced pressure
3. customto give a brown oil
4. additioncontaining two isomers
5. customThe 1-methyl3 and 2-methyl isomers were separated by column chromatography on silica gel with ethyl acetate as eluant