Synthesis and chemical reactivity of novel pyrano[3,2-c]quinoline-3-carbonitriles

Abstract

Reaction of 6-methyl-4,5-dioxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carboxaldehyde (1) with hydroxylamine hydrochloride under different reaction conditions produced a novel pyrano[3,2-c]quinoline derivatvies 2-5. Ring opening ring closure reactions of pyrano[3,2-c]quinoline-3-carbonitrile 2 with some nitrogen nucleophiles afforded the novel 3-heteroaryl-4-hydroxyquinolines. While, treatment of carbonitrile 3 with some nitrogen nucleohilic reagents produced a diversity of annulated pyrano[3,2-c]quinolines. The chemical reactivity of the prepared pyrano[3,2-c]quinoline-3-carbonitriles 2 and 3 is widely different depending on the different reactivity of pyran-2-one and pyran-4-one moieties toward the nucleophilic reagents as well as the functional groups present in pyrone rings