抄録
On nitration of 9-phenylxanthylium salt (I) with a mixed acid, 9-mononitrophenyl-xanthylium salt was obtained in 99% yield. The treatment of 9-phenylthioxanthylium salt (II) in the same condition gave a dinitrated product. Various nitration conditions were examined to obtain a mononitrated product. In order to determine the positions of the nitro group, various derivatives of I and II were synthesized. On the other hand, acetamido compounds derived from mononitrated I was separated into two isomers. It was thus proved that they were 9-(m-acetamidophenyl) xanthene (IVa) and 9-(p-acetamidophenyl) xanthene (IVb) in the ratio of 4.5 to 1.0, while mononitrated II gave 9-(m-acetamidophenyl) thioxanthene (XVa) and 9-(p-acetamidophenyl)-thioxanthene (XVb) in the ratio of 1.0 to 1.25. These results were particularly surprising in view of the fact that II was nitrated much easier than the oxygen analog I and also the p-nitro derivative was formed more than the m-nitro derivative.
