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 | |
ECHA InfoCard | 100.001.542 |
EC Number |
|
102490 | |
KEGG | |
PubChem CID | |
RTECS number |
|
UNII | |
CompTox Dashboard (EPA) | |
| |
| |
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 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). |
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]
Carl Graebe and Carl Glaser first isolated the compound from coal tar in 1872. [4]
Few carbazole production methods are economically viable, due to limited demand. During coal tar distillation, carbazole concentrates in the anthracene distillate and must be removed before anthraquinone production; that waste product is the major industrial carbazole source. [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]
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]
A third 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 released and the carbazole is formed. [11] [12]
Diphenylamine derivatives, being electron rich, naturally oxidize to carbazoles when heated in air. [13] A similar reaction is the Mallory reaction:
Substituted carbazoles are most easily synthesized with transition metal coupling reactions. For applications that transition-metal impurities in the final product might inhibit, an alternative is nucleophilic aromatic substitution on dibenzothiophene dioxide. [14]
Carbazoles occur naturally in carbazole alkaloids. Carbazole alkaloids with unsubstituted benzene rings occur rarely. Olivacin has been found in the bark of Aspidosperma olivaceum and ellipticin in Ochrosia elliptica . [15] Some carbazole alkaloids, especially glybomin B, have been isolated from Glycosmis pentaphylla . [16]
As carbazoles have a relatively rich UV-visible light spectrum, they see application as pigments [4] and photocatalysts. [17] The parent carbazole is used in Hydron Blue production [4] and aminoethylcarbazole is used in pigment violet 23 production. [18]
Carbazoles stabilize triplet emitters in certain light-emitting diodes; [4] in general, they are electron photodonors (hole acceptors). [19]
Carbazole electrochemically oxidizes to a conductive polymer, which has not achieved substantial industrial use. [20] 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.
Pentaerythritol is an organic compound with the formula C(CH2OH)4. The molecular structure can be described as a neopentane with one hydrogen atom in each methyl group replaced by a hydroxyl (–OH) group. It is therefore a polyol, specifically a tetrol.
Anthracene is a solid polycyclic aromatic hydrocarbon (PAH) of formula C14H10, consisting of three fused benzene rings. It is a component of coal tar. Anthracene is used in the production of the red dye alizarin and other dyes. Anthracene is colorless but exhibits a blue (400–500 nm peak) fluorescence under ultraviolet radiation.
Quinoline is a heterocyclic aromatic organic compound with the chemical formula C9H7N. It is a colorless hygroscopic liquid with a strong odor. Aged samples, especially if exposed to light, become yellow and later brown. Quinoline is only slightly soluble in cold water but dissolves readily in hot water and most organic solvents. Quinoline itself has few applications, but many of its derivatives are useful in diverse applications. A prominent example is quinine, an alkaloid found in plants. Over 200 biologically active quinoline and quinazoline alkaloids are identified. 4-Hydroxy-2-alkylquinolines (HAQs) are involved in antibiotic resistance.
Benzofuran is the heterocyclic compound consisting of fused benzene and furan rings. This colourless liquid is a component of coal tar. Benzofuran is the structural nucleus of many related compounds with more complex structures. For example, psoralen is a benzofuran derivative that occurs in several plants.
Camphene is a bicyclic organic compound. It is one of the most pervasive monoterpenes. As with other terpenes, it is insoluble in water, flammable, colorless, and has a pungent smell. It is a minor constituent of many essential oils such as turpentine, cypress oil, camphor oil, citronella oil, neroli, ginger oil, valerian, and mango. It is produced industrially by isomerization of the more common alpha-pinene using a solid acid catalyst such as titanium dioxide.
Salicylic aldehyde (2-hydroxybenzaldehyde) is an organic compound with the formula C6H4OH(CHO). Along with 3-hydroxybenzaldehyde and 4-hydroxybenzaldehyde, it is one of the three isomers of hydroxybenzaldehyde. This colorless oily liquid has a bitter almond odor at higher concentration. Salicylaldehyde is a precursor to coumarin and a variety of chelating agents.
Methacrylic acid, abbreviated MAA, is an organic compound with the formula CH2=C(CH3)CO2H. This colorless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its esters, especially methyl methacrylate (MMA), and to poly(methyl methacrylate) (PMMA).
Succinic anhydride, is an organic compound with the molecular formula (CH2CO)2O. This colorless solid is the acid anhydride of succinic acid.
Rhenium(VII) oxide is the inorganic compound with the formula Re2O7. This yellowish solid is the anhydride of HOReO3. Perrhenic acid, Re2O7·2H2O, is closely related to Re2O7. Re2O7 is the raw material for all rhenium compounds, being the volatile fraction obtained upon roasting the host ore.
Antimony trifluoride is the inorganic compound with the formula SbF3. Sometimes called Swarts' reagent, it is one of two principal fluorides of antimony, the other being SbF5. It appears as a white solid. As well as some industrial applications, it is used as a reagent in inorganic and organofluorine chemistry.
Phthalimide is the organic compound with the formula C6H4(CO)2NH. It is the imide derivative of phthalic anhydride. It is a sublimable white solid that is slightly soluble in water but more so upon addition of base. It is used as a precursor to other organic compounds as a masked source of ammonia.
Dimethyl carbonate (DMC) is an organic compound with the formula OC(OCH3)2. It is a colourless, flammable liquid. It is classified as a carbonate ester. This compound has found use as a methylating agent and as a co-solvent in lithium-ion batteries. Notably, dimethyl carbonate is a weak methylating agent, and is not considered as a carcinogen. Instead, dimethyl carbonate is often considered to be a green reagent, and it is exempt from the restrictions placed on most volatile organic compounds (VOCs) in the United States.
Thiophosphoryl chloride is an inorganic compound with the chemical formula PSCl3. It is a colorless pungent smelling liquid that fumes in air. It is synthesized from phosphorus chloride and used to thiophosphorylate organic compounds, such as to produce insecticides.
Hexachlorobutadiene, (often abbreviated as "HCBD") Cl2C=C(Cl)C(Cl)=CCl2, is a colorless liquid at room temperature that has an odor similar to that of turpentine. It is a chlorinated aliphatic diene with niche applications but is most commonly used as a solvent for other chlorine-containing compounds. Structurally, it has a 1,3-butadiene core, but fully substituted with chlorine atoms.
Indole is an organic compound with the formula C6H4CCNH3. Indole is classified as an aromatic heterocycle. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered pyrrole ring. Indoles are derivatives of indole where one or more of the hydrogen atoms have been replaced by substituent groups. Indoles are widely distributed in nature, most notably as amino acid tryptophan and neurotransmitter serotonin.
Diethylaluminium chloride, abbreviated DEAC, is an organoaluminium compound. Although often given the chemical formula (C2H5)2AlCl, it exists as a dimer, [(C2H5)2AlCl]2 It is a precursor to Ziegler-Natta catalysts employed for the production of polyolefins. The compound is also a Lewis acid, useful in organic synthesis. The compound is a colorless waxy solid, but is usually handled as a solution in hydrocarbon solvents. It is highly reactive, even pyrophoric.
Hexafluorobenzene, HFB, C
6F
6, or perfluorobenzene is an organofluorine compound. In this derivative of benzene, all hydrogen atoms have been replaced by fluorine atoms. The technical uses of the compound are limited, although it has some specialized uses in the laboratory owing to distinctive spectroscopic properties.
The diisopropylbenzenes(DIPB) are organic compounds with the formula C6H4(CH(CH3)2)2. Three isomers exist: 1,2- 1,3-, and 1,4-diisopropylbenzene. All are colorless liquids, immiscible in water, with similar boiling points. They are classified are aromatic hydrocarbons bearing a pair of isopropyl (CH(CH3)2) substituents. DIPB has been referred to as "a common diluent" alongside hexane.
o-Cymene is an organic compound classified as an aromatic hydrocarbon. Its structure consists of a benzene ring ortho-substituted with a methyl group and an isopropyl group. It is a flammable colorless liquid which is nearly insoluble in water but soluble in organic solvents.
m-Cymene is an organic compound classified as an aromatic hydrocarbon. Its structure consists of a benzene ring meta-substituted with a methyl group and an isopropyl group. It is a flammable colorless liquid which is nearly insoluble in water but soluble in organic solvents.
{{cite encyclopedia}}
: CS1 maint: multiple names: authors list (link)