Carbazole
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| Names | |
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| IUPAC name
9H-carbazole
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| Other names
9-azafluorene, dibenzopyrrole, diphenylenimine, diphenyleneimide, USAF EK-600
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| Identifiers | |
3D model (JSmol)
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| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.001.542 |
| KEGG | |
PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| C12H9N | |
| Molar mass | 167.206 g mol−1[1] |
| Density | 1.301g/cm^3 |
| Melting point | 246.3 °C[1] |
| Boiling point | 354.69 °C[1] |
| Hazards | |
| Flash point | 220 °C[1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Carbazole is an aromatic heterocyclic organic compound. It has a tricyclic structure, consisting of two six-membered benzene ring 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 4a-9a double bond in carbazole).
Synthesis
A classic laboratory organic synthesis for carbazole is the Borsche-Drechsel cyclization.[2][3]
Borsche-Drechsel synthesis
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
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.[5][6][7]
Supply and Demand
2010 and 2011 have seen wide spread shortages of Carbazole.
Use
Carbozole is used in the production of Pigment Violet 23.
Related aromatic compounds
References
- ^ a b c d Lide, David R. (2007). CRC Handbook of Chemistry and Physics, 88th Edition. CRC Press. pp. 3–86. ISBN 978-0849304880.
- ^ W. Borsche (1908). "Ueber Tetra- und Hexahydrocarbazolverbindungen und eine neue Carbazolsynthese. (Mitbearbeitet von. A. Witte und W. Bothe.)". Justus Liebig's Annalen der Chemie. 359 (1–2): 49–80. doi:10.1002/jlac.19083590103.
- ^ E. Drechsel (1888). "Ueber Elektrolyse des Phenols mit Wechselströmen". Journal für praktische Chemie. 38 (1): 65–74. doi:10.1002/prac.18880380105.
- ^ Organic Syntheses, Coll. Vol. 4, p.884 (1963); Vol. 30, p.90 (1950). Link
- ^ Graebe-Ullmann reaction
- ^ Carl Graebe and Fritz Ullmann (1896). "Ueber eine neue Carbazolsynthese". Justus Liebig's Annalen der Chemie. 291 (1): 16–17. doi:10.1002/jlac.18962910104.
- ^ O. Bremer (1934). "Über die Bedeutung der Graebe-Ullmannschen Carbazolsynthese und deren Übertragung auf N-substituierte Pyridino-triazole". Justus Liebigs Annalen der Chemie. 514: 279–291. doi:10.1002/jlac.19345140116.