William F. O'Connor

Ozonolysis of polycyclic aromatics. V. Naphthacene and 5,12-naphthacenequinone

Abstract Ozonization of naphthacene ( I ) with one molar equivalent of ozone gave 5,12-naphthacenequinone ( II ). Further, I and II absorb, respectively, three and two molar equivalents of ozone to yield, presumably via Criegees zwitterion ( III ), an unstable, probably monomeric ozonide ( IV ) in inert solvent methylene chloride, and a dimethoxy peracetal ( V ) in methanol. IV and V have been oxidized to 2,3-anthraquinonedicarboxylic acid ( VI ). VI was characterized by esterification to 2,3-dicarbomethoxyanthraquinone ( VII ), dehydration to 2,3-anthraquinonedicarboxylic anhydride ( VIII ), reduction to 2,3-anthracenedicarboxylic acid ( IX ) and its anhydride ( X ), and decarboxylation to anthraquinone ( XI ). These ozonolysis results are rationalized in terms of the initial addition of ozone to the conjugate 5,12-positions of I to give II via transition state Ia , followed by the addition of ozone to the 1,2- and 3,4-bonds of II via transition state IIa ∗ to give the observed ozonolysis products.

A bench-scale preparation of thioacetamide

The bench-scale preparation of thioacetamide presented is a modification of an earlier technique.