Английская Википедия:Carbazole
Шаблон:Chembox Carbazole is an aromatic heterocyclic organic compound. It has a tricyclic structure, consisting of two six-membered benzene rings fused on either side of a five-membered nitrogen-containing ring. The compound's structure is based on the indole structure, but in which a second benzene ring is fused onto the five-membered ring at the 2–3 position of indole (equivalent to the 9a–4a double bond in carbazole, respectively).
Carbazole is a constituent of tobacco smoke.[1]
Synthesis
Шаблон:Anchor A classic laboratory organic synthesis for carbazole is the Borsche–Drechsel cyclization.[2][3]
In the first step, phenylhydrazine is condensed with cyclohexanone to the corresponding imine. The second step is a hydrochloric acid-catalyzed rearrangement reaction and ring-closing reaction to tetrahydrocarbazole. In one modification, both steps are rolled into one by carrying out the reaction in acetic acid.[4] In the third step, this compound is oxidized by red lead to carbazole itself.
Another classic is the Bucherer carbazole synthesis, which uses a naphthol and an aryl hydrazine.[5]
A third method for the synthesis of carbazole is the Graebe–Ullmann reaction.
In the first step, an N-phenyl-1,2-diaminobenzene (N-phenyl-o-phenylenediamine) is converted into a diazonium salt which instantaneously forms a 1,2,3-triazole. The triazole is unstable and at elevated temperatures, nitrogen is released and the carbazole is formed.[6][7]
Applications
Aminoethylcarbazole is used in the production of pigment violet 23.
Related aromatic compounds
References
External links
