An efficient and solvent-free one-pot multi-component synthesis of novel highly substituted pyrido[2′,3′:3,4]pyrazolo[1,5-<i>a</i>]pyrimidine-3-carbonitrile derivatives catalyzed by tetramethylguanidine

An efficient solvent-free access towards highly substituted pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine-3-carbonitrile derivatives has been established through multi-component reaction of 1H‐pyrazolo[3,4‐b]pyridin‐3‐amine, aldehyde, 3-(1H-indol-3-yl)-3-oxopropanenitrile catalyzed by 1,1,3,3-tetramethylguanidine (TMG). The reaction allows the formation of one C−C and two C−N bonds with high yield. The significant features of this solvent-free reaction include mild reaction condition, readily accessible substrates, short reaction time, excellent yield, and broad substrate scopes as well as simple one-pot operation, no column chromatographic purification, which makes this strategy highly attractive.