Abstract
An efficient and concise practical protocol for the synthesis of novel aza-fused polysubstituted pyrido[2′,3′:3,4]pyrazolo[1,5-a]pyrimidine derivatives from a readily available aromatic aldehyde, acetophenone and 1H‐pyrazolo[3,4‐b]pyridin‐3‐amine in presence of Ba(OH)2, under transition metal-free conditions, has been established. This transformation presumably occurs through a sequential Aldol reaction, imine-formation, intramolecular N-cyclization, auto-oxidation sequence of reactions. This protocol, which includes the formation of new C–C and C–N bonds, features a wide substrate scope with a broad range of functional group tolerance.
Graphical Abstract
Disclosure statement
No potential conflict of interests was reported by the authors.
Supporting Information S1
Experimental details, 1H NMR and 13C NMR spectra for all compounds were provided as Supplementary Information.