Carbonyl and thiocarbonyl compounds. XII. Synthetic Experiments with Diazoxanthenes

9-Diazothioxanthene reacts with phenanthraquinone as well as with 3,4-dichloro-1,2-naphthoquinone giving the cyclic ethers 4 and 5 , respectively. The action of hydrochloric acid on the products is stressed. The cyclic ethers 7a and 7b are obtained from the reaction between 9-diazo-1,2-benzoxanthene and tetrachloro- or tetrabromo-o-benzoquinone. Authentic sample of 7b could be obtained by the reaction of 9,9-dichloro-1,2-benzoxanthene with tetrabromocatechol. 9-Diazoxanthene reacts with 1,4-benzo- and -naphthoquinone to give the pyrazolines 8a and 9a respectively, which readily give diacetyl derivatives upon acetylation.