Studies on Tropolone Derivatives

The authors have obtained all the substitution products possible of formation by the bromination of tropolone2~';~ .~~>. Those include two kinds of monobromo compound (o-: m.p. 108, p-: m.p. 191), two kinds of dibromo compound (o, o-: m.p. 160, o, p-: m.p. 153) and one kind of tribromo compound (m.p. 124). It had also been shown that during the bromination of tropolone or o-bromotropolone in carbon tetrachloride orr chloroform, a red or a yellowish orange complex is obtained as an intermediate and that the decomposition of this complex with water yielded a mixture of variously substituted bromotropolones. A tentative formula of an unsaturated tropoquinonoid structure, as shown in (A), was given for this complex2~.