Substituted quinolinones Part 23. Synthesis of 6 ethyl 4,5 dioxo 5,6 dihydro 4 H pyrano[3,2 c ]quinoline 3 carboxaldehyde and its chemical behavior towards hydroxylamine hydrochloride

Abstract

The synthesis of novel 6-ethyl-4,5-dioxo-5,6-dihydro-4H-pyrano[3,2-c]quinoline-3-carbox-aldehyde is described via Vilsmeier-Haack reaction of 3-acetyl-1-ethyl-4-hydroxyquinolin-2(1H)-one. The reaction of titled aldehyde with hydroxylamine hydrochloride, under different conditions, revealed its distinctive chemical behavior and a variety of products were obtained. This study revealed existence of ring-opening ring-closure (RORC) on treatment with hydroxylamine hydrochloride in both acetic acid and/or ethanolic potassium hydroxide. The structure of the new products was deduced on basis of their analytical and spectral data.