Carbazole
From Wikipedia, the free encyclopedia
| Carbazole | |
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| IUPAC name | 9H-carbazole |
| Other names | 9-azafluorene, dibenzopyrrole, diphenylenimine, diphenyleneimide, USAF EK-600 |
| Identifiers | |
| CAS number | [86-74-8] |
| Properties | |
| Molecular formula | C12H9N |
| Molar mass | 167.206 g mol−1[1] |
| Melting point |
246.3 °C[1] |
| Boiling point |
354.69 °C[1] |
| Hazards | |
| Flash point | 220 °C[1] |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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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).
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.
A second method for the synthesis of Carbazol is the Graebe-Ullmann reaction. In a first step a N-phenyl-1,2-diaminobenzene (N-phenyl-o-phenylenediamine) is converted into a diazoniumsalt which instantaniuosly 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]
Safety information for carbazole, from the Chemistry Department at Oxford University, is available here.
[edit] Related aromatic compounds
[edit] References
- ^ a b c d Lide, David R. (2007). CRC Handbook of Chemistry and Physics, 88th Edition. CRC Press, 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:.
- ^ E. Drechsel (1888). "Ueber Elektrolyse des Phenols mit Wechselströmen". Journal für praktische Chemie 38 (1): 65–74. doi:.
- ^ 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:.
- ^ 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:.
