Pot-, Atom- and Step-Economic (PASE) Multicomponent Approach to the 5-(Dialkylphosphonate)-Substituted 2,4-Diamino-5H-chromeno[2,3-b]pyridine Scaffold

A new multicomponent reaction is reported: the one-pot transformation of salicylaldehydes, 2-aminoprop-1-ene-1,1,3-tricarbonitrile (malononitrile dimer), and trialkylphosphites results in the efficient formation of (2,4-diamino-3-cyano-5H-chromeno[2,3-b]pyridin-5-yl)phosphonates. The scope of this one-pot reaction was investigated. The isolation of substituted phosphonates is very easy. The optimized reaction conditions and a mechanistic rationale for the complex multicomponent transformation are presented. This facile PASE approach offers a powerful tool for the selective formation of new types of functionalized 5-P-substituted 2,4-diamino-5H-chromeno[2,3-b]pyridine scaffolds containing the phosphonate fragment, which are promising compounds for various biomedical applications, among them the treatment of human inflammatory diseases and cancer therapy.