A direct synthetic route to fused tricyclic quinolones from 2,3-diaminoquinolin-4(1 <i>H</i> )one

Abstract

Abstract Fused tricyclic heterocycles are useful compounds in many areas of chemistry. In this study, 2,3-diaminoquinolin-4(1 H )one ( 5 ), a key intermediate for the preparation of tricyclic compounds, was prepared from isatoic anhydride in four steps with high yields under mild conditions and an easy workup, with most of the reactions carried out in aqueous medium. Compound 5 was transformed into a series of tricyclic fused products 8 and 9 .