8-Hydroxyquinoline
{{chembox
| Reference =
| ImageFile_Ref = {{chemboximage|correct|??}}
| ImageFile = 8-Hydroxychinolin.svg
| ImageSize = 150px
| ImageAlt = Skeletal formula of 8-hydroxyquinoline
| ImageFile1 = 8-Hydroxyquinoline 3D ball.png
| ImageSize1 = 160px
| ImageAlt1 = Ball-and-stick model of the 8-hydroxyquinoline molecule
| ImageFile2 = 8-Hydroxychinolin.jpg
| ImageSize2 = 150px
| ImageAlt2 = 8-hydroxyquinoline
| PIN = Quinolin-8-ol
| OtherNames = 1-Azanaphthalene-8-ol, Fennosan H 30, Hydroxybenzopyridine, Oxybenzopyridine, Oxychinolin, Oxyquinoline, Phenopyridine, Quinophenol, Oxine, 8-Quinolinol
|Section1={{Chembox Identifiers
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = D05321
| InChI = 1/C9H7NO/c11-8-5-1-3-7-4-2-6-10-9(7)8/h1-6,11H
| InChIKey = MCJGNVYPOGVAJF-UHFFFAOYAG
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 310555
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C9H7NO/c11-8-5-1-3-7-4-2-6-10-9(7)8/h1-6,11H
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = MCJGNVYPOGVAJF-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 148-24-3
| PubChem = 1923
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 1847
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 5UTX5635HP
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 48981
| SMILES = C1=CC2=C(C(=C1)O)N=CC=C2
}}
|Section2={{Chembox Properties
| Formula = C9H7NO
| MolarMass = 145.16 g/mol
| Appearance = White crystalline powder
| Density = 1.034 g/cm3
| MeltingPtC = 76
| BoilingPtC = 276
| Solubility =
}}
|Section6={{Chembox Pharmacology
| ATCCode_prefix = G01
| ATCCode_suffix = AC30
| ATC_Supplemental = {{ATC|A01|AB07}} {{ATC|D08|AH03}} {{ATC|R02|AA14}}
}}
|Section7={{Chembox Hazards
| GHSPictograms = {{GHS06}}{{GHS08}}{{GHS05}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|H301|H317|H318|H360D|H410}}
| PPhrases = {{P-phrases|P202|P273|P280|P301 + P310|P302 + P352|P305 + P351 + P338}}
| ExternalSDS = [https://www.sigmaaldrich.com/US/en/sds/sial/h6878 External MSDS]
| FlashPt =
| AutoignitionPt =
}}
}}
8-Hydroxyquinoline (also known as oxine) is an organic compound derived from the heterocycle quinoline. A colorless solid, its conjugate base is a chelating agent, which is used for the quantitative determination of metal ions.
In aqueous solution 8-hydroxyquinoline has a pKa value of ca. 9.9{{cite journal |last1=Albert |first1=A. |last2=Phillips |first2=J. N. |year=1956 |title=264. Ionization Constants of Heterocyclic Substances. Part II. Hydroxy-Derivatives of Nitrogenous Six-Membered Ring-Compounds |journal=Journal of the Chemical Society (Resumed) |volume=1956 |pages=1294–1304 |doi=10.1039/JR9560001294}} It reacts with metal ions, losing the proton and forming 8-hydroxyquinolinato-chelate complexes.
File:Mer-tris(8-hydroxyquinoline)aluminium(III)-from-xtal-2000-CM-3D-ellipsoids.png{{cite journal |last1=Cölle, M. |last2=Dinnebier, R. E. |last3=Brütting, W. |year=2002 |title=The structure of the blue luminescent δ-phase of tris(8-hydroxyquinoline)aluminium(III) (Alq3) |url=https://nbn-resolving.org/urn:nbn:de:bvb:384-opus4-679938 |journal=Chemical Communications |volume=2002 |issue=23 |pages=2908–9 |doi=10.1039/b209164j |pmid=12478807|s2cid=96135270 }}]]
The aluminium complex,{{cite journal |last1=Katakura, R. |last2=Koide, Y. |year=2006 |title=Configuration-Specific Synthesis of the Facial and Meridional Isomers of Tris(8-hydroxyquinolinate)aluminum (Alq3) |journal=Inorganic Chemistry |volume=45 |issue=15 |pages=5730–5732 |doi=10.1021/ic060594s |pmid=16841973}} is a common component of organic light-emitting diodes (OLEDs). Substituents on the quinoline ring affect the luminescence properties.{{cite journal |last1=Montes, V. A. |last2=Pohl, R. |last3=Shinar, J. |last4=Anzenbacher, P. Jr. |year=2006 |title=Effective Manipulation of the Electronic Effects and Its Influence on the Emission of 5-Substituted Tris(8-quinolinolate) Aluminum(III) Complexes |journal=Chemistry: A European Journal |volume=12 |issue=17 |pages=4523–4535 |doi=10.1002/chem.200501403 |pmid=16619313}}
In its photo-induced excited-state, 8-hydroxyquinoline converts to zwitterionic isomers, in which the hydrogen atom is transferred from oxygen to nitrogen.{{cite journal |last1=Bardez |first1=E. |last2=Devol |first2=I. |last3=Larrey |first3=B. |last4=Valeur |first4=B. |year=1997 |title=Excited-State Processes in 8-Hydroxyquinoline: Photoinduced Tautomerization and Solvation Effects |journal=The Journal of Physical Chemistry B |volume=101 |issue=39 |pages=7786–7793 |doi=10.1021/jp971293u}}
History
8-hydroxyquinoline was first obtained by Hugo Weidel and his student Albert Cobenzl in 1880. They decarboxylated so-called oxycinchoninic acid (from cinchonine) and characterized the resulting compound as melting at about 70°C. They identified that the hydroxy group is on the benzene ring (but not its particular place) and called the compound oxyquinoline and α-quinophenol.{{Cite journal |last1=Weidel |first1=H. |last2=Cobenzl |first2=A. |date=1880 |title=Über Derivate der Cinchoninsäure und des Chinolins |url=https://books.google.com/books?id=nCbzAAAAMAAJ&pg=PA862 |journal=Monatshefte für Chemie und verwandte Teile anderer Wissenschaften |language=de |volume=1 |issue=1 |pages=844–868 |doi=10.1007/BF01517113 |issn=1434-4475}}
In the following year more chemists found other ways to make the compound. Zdenko Hans Skraup discovered a way to synthesize substituted quinolines from substituted phenols and described three isomers of oxyquinoline, identifying the structure of 8-hydroxyquinoline.{{Cite patent|country=DE|number=14976|title=Verfahren zur Darstellung der Oxychinoline durch Behandlung von Mononitro- und Monamido-Phenolen mit Glycerin und Schwefelsäure|pubdate=1881-09-10|gdate=1881-02-16|invent1=Skraup|inventor1-first=Zdenko Hanus}} {{Ill|Otto Fischer (chemist)|lt=Otto Fischer|de|Otto Fischer (Chemiker)}} and his student Karl Bedall made the compound from a sulphonic acid independently at about the same time, but misidentified its structure.{{Cite journal |last1=Bedall |first1=Karl |last2=Fischer |first2=Otto |date=1881 |title=Ueber Oxychinolin aus Chinolinsulfosäure |url=https://books.google.com/books?id=XCDPAAAAMAAJ&pg=442 |journal=Berichte der Deutschen Chemischen Gesellschaft |language=de |volume=14 |issue=1 |pages=442–443 |doi=10.1002/cber.188101401101 |issn=1099-0682}}{{Cite journal |last=Fischer |first=Otto |date=1882 |title=Zur Geschichte der Oxychinoline |url=https://books.google.com/books?id=Mxb-NAhE8K4C&pg=PA1979 |journal=Berichte der Deutschen Chemischen Gesellschaft |language=de |volume=15 |issue=2 |pages=1979–1981 |doi=10.1002/cber.188201502123 |issn=1099-0682}}
By 1888 azo dyes were made from the compound.{{Cite book |last= |first= |url=https://books.google.com/books?id=wCDOAAAAMAAJ&pg=PA99 |title=Journal of the Society of Dyers and Colourists |date=1888 |publisher=Society of Dyers and Colourists |language=en}}
In the 1920s insoluble chelates of 8-hydroxyquinoline were discovered.{{Cite journal |last=Berg |first=R. |date=1927 |title=Neue Wege zur Bestimmung und Trennung der Metalle mit Hilfe von o-Oxychinolin |url=https://link.springer.com/article/10.1007/BF01390921 |journal=Zeitschrift für analytische Chemie |language=de |volume=71 |issue=5 |pages=171–185 |doi=10.1007/BF01390921 |issn=1618-2650}}
{{Section-stub|date=December 2024}}
Bioactivity
The complexes as well as the heterocycle itself exhibit antiseptic, disinfectant, and pesticide properties,{{cite journal |last=Phillips |first=J. P. |year=1956 |title=The Reactions of 8-Quinolinol |journal=Chemical Reviews |volume=56 |issue=2 |pages=271–297 |doi=10.1021/cr50008a003}}{{cite web |title=8-Hydroxyquinoline |url=http://www.online-medical-dictionary.org/definitions-8/8-hydroxyquinoline.html |url-status=dead |archive-url=https://web.archive.org/web/20161009000455/http://www.online-medical-dictionary.org/definitions-8/8-hydroxyquinoline.html |archive-date=2016-10-09 |access-date=2016-03-09 |publisher=Medical Dictionary Online}} functioning as a transcription inhibitor.{{cite web |title=8-Hydroxyquinoline |url=http://www.sigmaaldrich.com/US/en/product/sial/h6878
|access-date=2022-02-15 |publisher=Sigma-Aldrich}} {{Dubious|date=July 2024}} Its solution in alcohol is used in liquid bandages. It once was of interest as an anti-cancer drug.{{cite journal |last1=Shen, A. Y. |last2=Wu, S. N. |last3=Chiu, C. T. |year=1999 |title=Synthesis and Cytotoxicity Evaluation of some 8-Hydroxyquinoline Derivatives |journal=Journal of Pharmacy and Pharmacology |volume=51 |issue=5 |pages=543–548 |doi=10.1211/0022357991772826 |pmid=10411213 |s2cid=33085238|doi-access=free }}
A thiol analogue, 8-mercaptoquinoline is also known.{{cite journal|doi=10.1016/j.ccr.2004.08.024|title=Structural Chemistry of Complexes of (n-1)d10ns Metal Ions with β-N-Donor Substituted Thiolate Ligands (m=0, 2) |year=2005 |last1=Fleischer |first1=H. |journal=Coordination Chemistry Reviews |volume=249 |issue=7–8 |pages=799–827 }}
The roots of the invasive plant Centaurea diffusa release 8-hydroxyquinoline, which has a negative effect on plants that have not co-evolved with it.{{cite journal |last1=Vivanco, J.M. |last2=Bais, H.P. |last3=Stermitz, F.R. |last4=Thelen, G.C. |last5=Callaway, R.M. |year=2004 |title=Biogeographical variation in community response to root allelochemistry: novel weapons and exotic invasion |journal=Ecology Letters |volume=7 |issue=4 |pages=285–292 |doi=10.1111/j.1461-0248.2004.00576.x|bibcode=2004EcolL...7..285V }}
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See also
- Nitroxoline (5-nitro-8-hydroxyquinoline), an antiprotozoal drug
- PBT2
- QUPIC
- Ionophore
- Trace metal detection test
References
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{{Antiseptics and disinfectants}}
{{Gynecological anti-infectives and antiseptics}}
{{Antiprotozoal agent}}
{{DEFAULTSORT:Hydroxyquinoline, 8-}}