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|Section2= |Section3= }} 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). ==Synthesis== A classic laboratory organic synthesis for carbazole is the Borsche–Drechsel cyclization. : 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.〔Organic Syntheses, Coll. Vol. 4, p.884 (1963); Vol. 30, p.90 (1950). (Link )〕 In the third step this compound is oxidized by Red lead to carbazole itself. Another classic is the Bucherer carbazole synthesis A second 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 set free and the carbazole is formed. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Carbazole」の詳細全文を読む スポンサード リンク
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