Chemistry:Carbazole

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Carbazole
Carbazole.png
Carbazole-3D-vdW.png
Carbazole ball-and-stick.png
Names
Preferred IUPAC name
9H-Carbazole[1]
Other names
9-azafluorene
dibenzopyrrole
diphenylenimine
diphenyleneimide
USAF EK-600
Identifiers
3D model (JSmol)
3956
ChEBI
ChEMBL
ChemSpider
DrugBank
EC Number
  • 201-696-0
102490
KEGG
RTECS number
  • FE3150000
UNII
Properties
C12H9N
Molar mass 167.211 g·mol−1
Density 1.301 g cm−3
Melting point 246.3 °C (475.3 °F; 519.5 K)[2]
Boiling point 354.69 °C (670.44 °F; 627.84 K)[2]
−117.4 × 10−6 cm3 mol−1
Hazards
GHS pictograms GHS08: Health hazardGHS09: Environmental hazard
GHS Signal word Warning
H341, H351, H400, H411, H413
P201, P202, P273, P281, P308+313, P391, P405, P501
Flash point 220 °C (428 °F; 493 K)[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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.[3]

Synthesis

A classic laboratory organic synthesis for carbazole is the Borsche–Drechsel cyclization.[4][5]

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.[6] 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.[7]

Bucherer carbazole synthesis

A third method for the synthesis of carbazole is the Graebe–Ullmann reaction.

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.[8][9]

Fluorescence of (9H-carbazol-9-yl)(2,4-dichlorophenyl) methanone

Applications

Aminoethylcarbazole is used in the production of pigment violet 23.

CI Pigment Violet 23 synthesis: U.S. Patent 4,345,074

Related aromatic compounds

References

  1. International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. pp. 212. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4. 
  2. 2.0 2.1 2.2 Lide, David R. (2007). CRC Handbook of Chemistry and Physics, 88th Edition. CRC Press. pp. 3–86. ISBN 978-0-8493-0488-0. 
  3. Talhout, Reinskje; Schulz, Thomas; Florek, Ewa; Van Benthem, Jan; Wester, Piet; Opperhuizen, Antoon (2011). "Hazardous Compounds in Tobacco Smoke". Int. J. Environ. Res. Public Health 8 (12): 613–628. doi:10.3390/ijerph8020613. PMID 21556207. 
  4. W. Borsche (1908). "Ueber Tetra- und Hexahydrocarbazolverbindungen und eine neue Carbazolsynthese. (Mitbearbeitet von. A. Witte und W. Bothe.)" (in German). Justus Liebigs Ann. Chem. 359 (1–2): 49–80. doi:10.1002/jlac.19083590103. https://zenodo.org/record/1427575. 
  5. E. Drechsel (1888). "Ueber Elektrolyse des Phenols mit Wechselströmen" (in de). J. Prakt. Chem. 38 (1): 65–74. doi:10.1002/prac.18880380105. https://zenodo.org/record/1427938. 
  6. Rogers, Crosby U.; Corson, B. B. (1950). "1,2,3,4-Tetrahydrocarbazole (Carbazole, 1,2,3,4-tetrahydro-)". Organic Syntheses 30: 90. doi:10.15227/orgsyn.030.0090. http://www.orgsyn.org/demo.aspx?prep=CV4P0884. ; Collective Volume, 4, pp. 884 
  7. Wang, Zerong (2010). "Bucherer Carbazole Synthesis". Comprehensive Organic Name Reactions and Reagents. doi:10.1002/9780470638859.conrr120. ISBN 9780470638859. 
  8. Carl Graebe; Fritz Ullmann (1896). "Ueber eine neue Carbazolsynthese" (in German). Justus Liebigs Ann. Chem. 291 (1): 16–17. https://zenodo.org/record/1427487. 
  9. O. Bremer (1934). "Über die Bedeutung der Graebe-Ullmannschen Carbazolsynthese und deren Übertragung auf N-substituierte Pyridino-triazole" (in German). Justus Liebigs Ann. Chem. 514 (1): 279–291. doi:10.1002/jlac.19345140116. 

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