Microwave‐assisted synthesis and heterocyclic functionalization of chromenopyridines on calixarene scaffold

A three‐component one‐pot condensation reaction of chroman‐4‐one with ethyl 2‐cyanoacetate and various aldehydes in the presence of ammonium acetate afforded a series of 2‐oxo‐4‐phenyl‐1,5‐dihydro‐2H‐chromeno[4,3‐b]pyridine‐3‐carbonitrile. These heterocycles have been converted to chloropyridine derivatives and appended to macrocyclic calix[4]arene scaffold through aromatic nucleophilic substitution under microwave irradiation. In this study, the microwave‐assisted functionalization of the lower rim of calix[4]arene has been considered the only appropriate tool because the conventional heating did not lead to any new product after 72 hours of heating under thermal condition.