Carbazole
Names
Preferred IUPAC name
Other names
9-azafluorene dibenzopyrrole diphenylenimine diphenyleneimide USAF EK-600
Identifiers
3956
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
100.001.542
EC Number
102490
KEGG
RTECS number
UNII
InChI=1S/C12H9N/c1-3-7-11-9(5-1)10-6-2-4-8-12(10)13-11/h1-8,13H
Y Key: UJOBWOGCFQCDNV-UHFFFAOYSA-N
Y InChI=1/C12H9N/c1-3-7-11-9(5-1)10-6-2-4-8-12(10)13-11/h1-8,13H
Key: UJOBWOGCFQCDNV-UHFFFAOYAV
Properties
C 12 H 9 N
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 labelling :
Warning
H341 , H351 , H400 , H411 , H413
P201 , P202 , P273 , P281 , P308+P313 , 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).
Chemical compound
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]
History
Carl Graebe and Carl Glaser first isolated the compound from coal tar in 1872.[4]
Production
Few carbazole production methods are economically viable, due to limited demand. During coal tar distillation, it concentrates in the anthracene distillate and must be removed before anthraquinone production.[4] [5] Polar compounds (e.g., ketones) selectively precipitate it from the anthracene; a more modern technique is simply selective crystallization from molten coal tar at high temperature[4] or low pressure (70 mmHg).[6]
A classic laboratory organic synthesis for carbazole is the Borsche–Drechsel cyclization .[7] [8]
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 .[9] 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.[10]
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.[11] [12]
Fluorescence of (9H-carbazol-9-yl)(2,4-dichlorophenyl) methanone
Diphenylamine derivatives, being electron rich , naturally oxidize to carbazoles when heated in air.[13]
Substituted carbazoles are most easily synthesized with transition metal coupling reactions . For applications prohibiting transition-metal impurities in the final product, an alternative is nucleophilic aromatic substitution on dibenzothiophene dioxide.[14]
Applications
As carbazoles have a relatively rich UV-visible light spectrum, they see application as pigments[4] and photocatalysts .[15] The parent carbazole is used in Hydron Blue production[4] and aminoethylcarbazole is used in pigment violet 23 production.[16]
Pigment Violet 23 synthesis
Carbazoles stabilize triplet emitters in certain light-emitting diodes ;[4] in general, they are electron photodonors (hole acceptors).[17]
Carbazole electrochemically oxidizes to a conductive polymer , which has not achieved substantial industrial use.[18] Polyvinylcarbazole is useful in the electrical and electronic industries, and certain carbazole novolaks are extremely heat resistant.[4]
In organic chemistry, carbazole proper is also an ingredient for several bioactive molecules . The insecticide Nirosan ,[4] the cocaine overdose antidote Rimcazole , and the veterinary NSAID Carprofen are all made from carbazole. The topoisomerase II inhibitor ellipticine fuses carbazole to a pyridine ring.
Related aromatic compounds
References
^ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 . The Royal Society of Chemistry . p. 212. doi :10.1039/9781849733069 . ISBN 978-0-85404-182-4 .
^ a b c Lide, David R. (2007). CRC Handbook of Chemistry and Physics, 88th Edition . CRC Press . pp. 3–86. ISBN 978-0-8493-0488-0 .
^ 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 . PMC 3084482 . PMID 21556207 .
^ a b c d e f g h Collin, Gerd; Höke, Hartmut; Talbiersky, Jörg. "Carbazole". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi :10.1002/14356007.a05_059.pub2 . ISBN 978-3527306732 . {{cite encyclopedia }}
: CS1 maint: multiple names: authors list (link )
^ Cofrancesco, A. J., "Anthraquinone", Kirk-Othmer Encyclopedia of Chemical Technology , New York: John Wiley, p. 5, doi :10.1002/0471238961.0114200803150618.a01 , ISBN 9780471238966
^ Betts, W. D., "Tar and Pitch", Kirk-Othmer Encyclopedia of Chemical Technology , New York: John Wiley, p. 5, doi :10.1002/0471238961.20011802052020.a01 , ISBN 9780471238966
^ W. Borsche (1908). "Ueber Tetra- und Hexahydrocarbazolverbindungen und eine neue Carbazolsynthese. (Mitbearbeitet von. A. Witte und W. Bothe.)" . Justus Liebigs Ann. Chem. (in German). 359 (1–2): 49–80. doi :10.1002/jlac.19083590103 .
^ E. Drechsel (1888). "Ueber Elektrolyse des Phenols mit Wechselströmen" . J. Prakt. Chem. (in German). 38 (1): 65–74. doi :10.1002/prac.18880380105 .
^ 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 ; Collected Volumes , vol. 4, p. 884 .
^ Wang, Zerong (2010). "Bucherer Carbazole Synthesis". Comprehensive Organic Name Reactions and Reagents . pp. 549–552. doi :10.1002/9780470638859.conrr120 . ISBN 9780470638859 .
^ Carl Graebe ; Fritz Ullmann (1896). "Ueber eine neue Carbazolsynthese" . Justus Liebigs Ann. Chem. (in German). 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 Ann. Chem. (in German). 514 (1): 279–291. doi :10.1002/jlac.19345140116 .
^ Vogt, Peter F.; Gerulis, John J. "Amines, Aromatic". Ullmann's Encyclopedia of Industrial Chemistry . Vol. 2. Weinheim: Wiley-VCH. p. 703. doi :10.1002/14356007.a02_037 . ISBN 978-3527306732 .
^ Bhanuchandra, M.; Yorimitsu Hideki. "Dibenzothiophene 5,5-dioxide". Encyclopedia of Reagents for Organic Synthesis . doi :10.1002/047084289X.rn02046 .
^ Rizzo, Carmelo J. (2005). "N-Methylcarbazole". N -Methylcarbazole . Encyclopedia of Reagents for Organic Synthesis . doi :10.1002/047084289X.rn00578 . ISBN 0-471-93623-5 .
^ U.S. patent 4,345,074
^ Ying Wang, "Photoconductive polymers", Kirk-Othmer Encyclopedia of Chemical Technology , New York: John Wiley, p. 15, doi :10.1002/0471238961.1608152023011407.a01 , ISBN 9780471238966
^ Naarmann, Herbert. "Polymers, Electrically conducting". Ullmann's Encyclopedia of Industrial Chemistry . Vol. 29. Weinheim: Wiley-VCH. p. 309. doi :10.1002/14356007.a21_429 . ISBN 978-3527306732 .
External links