Abstract
A new synthetic method of 2-arylthio- or 2-alkylthio-p-benzoquinones (XV-XXI) was established through the application of the reaction of hydroquinone with sulfoxides. The reaction of hydroquinone with methyl aryl sulfoxides in the presence of perchloric acid, or with dialkyl sulfoxides in the presence of both perchloric acid and phosphoryl chloride, progressed easily to afford 2, 5-dihydroxyphenylarylmethylsulfonium perchlorates (I-III) or 2, 5-dihydroxyphenyldialkylsulfonium perchlorates (IV-VII). The treatment of these sulfonium perchlorates (I-VII) with potassium chloride or pyridine gave 2-arylthio- or 2-alkylthio-1, 4-dihydroxybenzenes (VIII-XIV) and alkyl chlorides or N-alkylpyridinium perchlorates, respectively. Thus it was shown that Hofmann's degradation did not take place in this case. Compounds VIII to XIV were easily oxidized by ferric chloride to 2-arylthio- or 2-alkylthio-p-benzoquinones (XV-XXI).
