Dimethylthioxanthones Formed by Condensation of 2-Mercaptobenzoic Acid with o-, or m-Xylene in Sulfuric Acid

抄録

Various dimethyl-substituted thioxanthones were prepared by the condensation reaction of 2-mercaptobenzoic acid and o-, m-, or p-xylene in sulfuric acid. Some of them are novel compounds (5, 11, 12, and 13). That is, from o-xylene, 1, 2-dimethyl (11) -, 2, 3-dimethyl (12) -, and 3, 4-dimethyl-thioxanthones (13) were formed in yields of 9.3, 37.1, and 12.8%, respectively. From m-xylene and p-xylene, 2, 4-dimethylthioxanthone (4) and 1, 4-dimethylthioxanthone (9), respectively, were obtained by the same condensation reaction. The structures were confirmed on the basis of spectral investigation and comparison with authentic materials obtained by another synthetic route : the cyclization of phenylthiobenzoic acids.