Reactive Troponoids and <i>o</i>-Aminophenol. III. The Reaction of 2-Bromo-7-methoxytropone

Abstract

Abstract The reaction of 2-bromo-7-methoxytropone with o-aminophenol gave 2-bromo-7-(o-hydroxyanilino)tropone (9), besides small amounts of cyclohepta[b][1,4]benzoxazin-6(11H)-one (10) and 15H-[1,4]benzoxazino[3′,2′ : 3,4]cyclohepta[2,1-b][1,4]benzoxazine (11). The heating of 9 with a strong acid afforded 6-bromocyclohepta[b][1,4]benzoxazine (13) quantitatively. On the other hand, the heating of 13 with o-aminophenol in ethanol gave 10, while in acetic acid a mixture of 10 and 11 was obtained. The mechanism of the formation of these products is discussed.