6533b871fe1ef96bd12d0e79
RESEARCH PRODUCT
Synthese von Benzo[b]thioxanthenen
Dieter GröschlHerbert MeierM. SchmidtAxel Mayersubject
chemistry.chemical_classificationchemistry.chemical_compoundKetonechemistryAutoxidationSulfoniumStereochemistryThioxanthenesRegioselectivityGeneral MedicineIsomerizationCatalysisAdductdescription
Synthesis of Benzo[b]thioxanthenes Benzo[b]thioxanthenes, heterocyclic compounds related to tetracenes and tetracyclines can be obtained by the reaction of 2H-benzo[b]thiete (1) and 1,4-naphthoquinones (3a–g). The primary cycloadducts 4a–g undergo an autoxidation process leading to the quinones 6a–g. The dihydroxy compound 4e shows an additional isomerization by a tetrafold H transfer (4e 5e′). Another preparative route to benzo[b]thioxanthenes makes use of the cycloadditon reaction of 1 and 1,4-epoxynaphthalenes (7a–d). The primary adducts can be transformed to the title compounds by catalytic dehydration processes (8a–d 9a-d). An alternate regioselective opening of the oxygen bridge can be performed by the action of trimethyliodosilane (8a 10a). Methylation of 9a furnishes the sulfonium salt 14a which rearranges in a strongly alkaline medium to 16a; in the presence of oxygen ketone 17a is generated.
year | journal | country | edition | language |
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1995-01-01 | Journal f�r Praktische Chemie/Chemiker-Zeitung |