Preparation and properties of some substituted quinazolino[3,2-b]-cinnolines

Abstract

The preparations of the substituted quinol 3-amino-2-(2,5-dihydroxybenzyl)quinazolin-4(3H)-one and some of its derivatives are described. When this quinol is oxidised with an acidic ferric chloride solution or with an aqueous sodium hydroxide solution a quinone was formed, but it spontaneously ring-closed to give quinazolino[3,2-b]-cinnoline-2,7(13H)-dione, which was isolated as the hydrochloride. When the oxidation of the quinol was carried out with an acidic hydrogen peroxide solution the ring-closed products also formed as an intermediate, which was immediately converted into 1,3,4-trichloroquinazoline[3,2-b]cinnoline-2,7(13H)-dione, and only this dione was then obtained.