| 摘要 |
<p>The invention relates to a process for the preparation of a 2,3,5,6-tetrasubstituted p-benzoquinone of general formula (I): (I) wherein R represents a bromine atom,or a C2-C6-acylthio or benzoylthio radical; wherein 2,3,5,6-tetramethylhydro-quinone or 2,3,5,6-tetramethyl-p-benzoquinone is reacted with bromine at elevated temperatures with exposure to light, and, if desired, the resulting 2,3,5,6-tetra- (bromomethyl)-p-benzoquinone is isolated as such or isolated and reacted with a thiocarboxylic acid of formula: R' - H wherein R' represents a C2-C6-acylthio radical or a benzoylthio radical to give the corresponding compound that is then isolated. The invention also relates to the compounds of formula (I) so obtained. These compounds are useful to acceed in a relatively simple manner to 4,8-dihydro-benzo ¢1,2-c:4,5-c'! dithiophene-4,8-dione.</p> |
