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On the Mechanism of the Thermal and Photolytic Cyclization of Diphenylamines to Carbazoles
Author(s) -
Wentrup C.,
Gaugaz M.
Publication year - 1971
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19710540743
Subject(s) - chemistry , thermal decomposition , carbazole , photodissociation , torr , atmospheric temperature range , photochemistry , ether , medicinal chemistry , thermal , organic chemistry , physics , thermodynamics , meteorology
The product of photolysis of di‐ p ‐tolyamine in petroleum ether is 3,6‐dimethylcarbazole. The primary product of gas‐phase thermolysis of di‐ p ‐tolylamine at 850–1000°/0.01–0.05 Torr is also 3,6‐dimethylcarbazole. In the higher temperature range monomethylcarbazole and carbazole are also formed. Thermolysis of tetra‐ p ‐tolylhydrazine at 800–1000° gives only di‐ p ‐tolylamine, the latter decomposing further in the higher temperature range. It is concluded that carbazole formation involves in both cases an electrocyclization of the ortho ‐positions, and not a rearrangement, and that diphenylaminyl is not an intermediate.