ChemInform Abstract: Selective Synthesis of New Tetracyclic Coumarin-Fused Pyrazolo[3,4-b]pyridines and Pyrazolo[3,4-b]pyridin-6(7H)-ones.
文摘
Depending on the reaction conditions, the three-component reaction of (I), (III), and an aldehyde affords three different compounds, i.e.