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Paper | Regular issue | Vol 98, No. 10, 2019, pp.1408-1422
Published online, 1st November, 2019
DOI: 10.3987/COM-19-14158
Fast, Solvent-Free, and Highly Efficient Synthesis of Pyrazolo[3,4-b]Pyridines Using Microwave Irradiation and Khso4 as A Reusable Green Catalyst

Jinjing Qin, Zhenhua Li,* Xiaomeng Sun, Yi Jin, and Weike Su

*Collaborative Innovation Centre of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, 18#, Chaowang Rd., Hangzhou, Zhejiang 310014, China


A simple, ecofriendly, and effective method was described for forming pyrazolo[3,4-b]pyridines from 5-aminopyrazoles and 3-formylchromones, in good to excellent yields, under microwave irradiation in solvent-free conditions using KHSO4 as a reusable catalyst. Some noteworthy features of this method were its cleanliness, short reaction time, easy work-up, and broad substrate tolerance. The catalyst was reused several times without losing activity.