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Record Information
Version2.0
Creation Date2014-08-29 05:52:38 UTC
Update Date2020-07-08 16:41:42 UTC
Accession NumberT3D4203
Identification
Common NameFuran
ClassSmall Molecule
DescriptionFuran is a member of the class of compounds known as furans. These are molecules containing a heterocyclic organic group consisting of a five-membered aromatic ring with four carbon atoms and one oxygen. Furan is aromatic because one of the lone pairs of electrons on the oxygen atom is delocalized into the ring, creating a 4n+2 aromatic system similar to benzene. Because of the aromaticity, furan is flat and lacks discrete double bonds. Furan is a colourless, flammable, highly volatile liquid with a boiling point close to room temperature (31°C). It is soluble in common organic solvents, including alcohol, ether, and acetone, but is insoluble in water. It has a strong ethereal odour. Furan is found in heat-treated (e.g. cooked, roasted, baked, pasteurized, and sterilized) commercial foods and is produced through thermal degradation of natural food constituents (PMID: 22641279). It can be found in roasted coffee, instant coffee, and processed baby foods (PMID: 22641279). In particular, the highest furan levels can be detected in coffee, with mean values between 42 and 3 660 ng/g for brewed coffee and roasted coffee beans. Furan can also be detected at levels between 0.2 and 3.2 ng/g in infant formula, from 22 to 24 ng/g in baked beans, from 13 to 17 ng/g in meat products, and from 23 to 24 ng/g in soups. In soy sauce, furan is detectable at 27 ng/g (PMID: 26483883). Research has indicated that coffee made in espresso makers and, above all, coffee made from capsules, contains more furan than that made in traditional drip coffee makers, although the levels are still within safe health limits. Various pathways have been reported for the formation of furan: (1) thermal degradation and/or thermal rearrangement of carbohydrates in the presence of amino acids, (2) thermal degradation of certain amino acids (aspartic acid, threonine, α-alanine, serine, and cysteine), (3) oxidation of ascorbic acid at higher temperatures, and (4) oxidation of polyunsaturated fatty acids and carotenoids (PMID: 26483883). Several studies have reported that furan formation occurs to a large extent during the Maillard reaction. The Maillard reaction involves the thermal degradation and rearrangement of carbohydrates (i.e. non-enzymatic browning reactions during food processing and cooking). Reducing hexoses often go through the Maillard reaction in the presence of amino acids and produce reactive intermediates such as 1-deoxy- and 3-deoxyosones, aldotetrose, and 2-deoxy-3-keto-aldotetrose. 2-Deoxy-3-keto-aldotetrose typically goes through retro-aldol cleavage leading to 3-deoxyosone which undergoes α-dicarbonyl cleavage, followed by oxidation and decarboxylation to form 2-deoxyaldotetrose, which is a direct precursor of furan. In addition to the formation of furan via carbohydrate degradation, furan can also be formed through thermal degradation of certain amino acids. Specifically, the amino acids that can form acetaldehyde and glycolaldehyde can produce furan by aldol condensation and cyclization (PMID: 26483883). Furan is toxic and may be carcinogenic. In particular, furan is a potent hepatotoxin and hepatocarcinogen in rodents, causing hepatocellular adenomas and carcinomas in rats and mice, and high incidences of cholangiocarcinomas in rats at doses ≥ 2 mg/kg (PMID: 22641279).
Compound Type
  • Cigarette Toxin
  • Industrial/Workplace Toxin
  • Metabolite
  • Organic Compound
  • Solvent
  • Synthetic Compound
Chemical Structure
Thumb
Synonyms
Synonym
1,4-Epoxy-1,3-butadiene
Divinylene oxide
Furane
Furfuran
Oxacyclopentadiene
Oxole
Tetrole
Chemical FormulaC4H4O
Average Molecular Mass68.074 g/mol
Monoisotopic Mass68.026 g/mol
CAS Registry Number110-00-9
IUPAC Namefuran
Traditional Namefuran
SMILESO1C=CC=C1
InChI IdentifierInChI=1S/C4H4O/c1-2-4-5-3-1/h1-4H
InChI KeyInChIKey=YLQBMQCUIZJEEH-UHFFFAOYSA-N
Chemical Taxonomy
Description belongs to the class of organic compounds known as heteroaromatic compounds. Heteroaromatic compounds are compounds containing an aromatic ring where a carbon atom is linked to an hetero atom.
KingdomOrganic compounds
Super ClassOrganoheterocyclic compounds
ClassHeteroaromatic compounds
Sub ClassNot Available
Direct ParentHeteroaromatic compounds
Alternative Parents
Substituents
  • Heteroaromatic compound
  • Furan
  • Oxacycle
  • Organic oxygen compound
  • Hydrocarbon derivative
  • Organooxygen compound
  • Aromatic heteromonocyclic compound
Molecular FrameworkAromatic heteromonocyclic compounds
External Descriptors
Biological Properties
StatusDetected and Not Quantified
OriginExogenous
Cellular Locations
  • Cytoplasm
  • Extracellular
Biofluid LocationsNot Available
Tissue LocationsNot Available
PathwaysNot Available
ApplicationsNot Available
Biological Roles
Chemical Roles
Physical Properties
StateLiquid
AppearanceNot Available
Experimental Properties
PropertyValue
Melting Point-85.6°C
Boiling Point32°C (89.6°F)
Solubility10 mg/mL at 25°C
LogP1.34
Predicted Properties
PropertyValueSource
Water Solubility15.9 g/LALOGPS
logP1.24ALOGPS
logP1.11ChemAxon
logS-0.63ALOGPS
pKa (Strongest Basic)-2.9ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count0ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area13.14 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity18.57 m³·mol⁻¹ChemAxon
Polarizability6.68 ųChemAxon
Number of Rings1ChemAxon
Bioavailability1ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Spectra
Spectra
Spectrum TypeDescriptionSplash KeyDeposition DateView
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-00kr-9000000000-4c50652f33a401ab3cae2017-09-12View Spectrum
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-00kr-9000000000-d007e0256578ac930b222017-09-12View Spectrum
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-00kr-9000000000-4c50652f33a401ab3cae2018-05-18View Spectrum
GC-MSGC-MS Spectrum - EI-B (Non-derivatized)splash10-00kr-9000000000-d007e0256578ac930b222018-05-18View Spectrum
Predicted GC-MSPredicted GC-MS Spectrum - GC-MS (Non-derivatized) - 70eV, PositiveNot Available2021-10-12View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-014i-9000000000-511af11e910184693aa12016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-014i-9000000000-fd05695071ee559e9be42016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-014i-9000000000-208e5dd03db999e390ff2016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-014i-9000000000-351aa9d338efe69d31ef2016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-014i-9000000000-acebecda0e70274875b12016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-014i-9000000000-1df91dbb0164452d0fd12016-08-03View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-014u-9000000000-41895048238024d76bc72021-09-22View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-00ku-9000000000-a223589b20bc67c79fe02021-09-22View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0udr-9000000000-056962459138c52c54c82021-09-22View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-00kf-9000000000-983ab9ff6334b0b9a5842021-09-22View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-00ke-9000000000-77469f3e4a080d7d36812021-09-22View Spectrum
Predicted LC-MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-00kg-9000000000-d4fe1a89a559171ed26a2021-09-22View Spectrum
MSMass Spectrum (Electron Ionization)splash10-00kr-9000000000-3bddc12b5a8dd3ca188d2014-09-20View Spectrum
1D NMR1H NMR Spectrum (1D, 90 MHz, CDCl3, experimental)Not Available2014-09-20View Spectrum
1D NMR13C NMR Spectrum (1D, 25.16 MHz, CDCl3, experimental)Not Available2014-09-23View Spectrum
1D NMR1H NMR Spectrum (1D, 100 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 100 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 1000 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 1000 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 200 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 200 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 300 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 300 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 400 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 400 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 500 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 500 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 600 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 600 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 700 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 700 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 800 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 800 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR1H NMR Spectrum (1D, 900 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
1D NMR13C NMR Spectrum (1D, 900 MHz, D2O, predicted)Not Available2021-09-25View Spectrum
Toxicity Profile
Route of ExposureNot Available
Mechanism of ToxicityFuran is a potent hepatotoxin and hepatocarcinogen in rodents, causing hepatocellular adenomas and carcinomas in rats and mice, and high incidences of cholangiocarcinomas in rats at doses ≥ 2 mg/kg bw. A genotoxic mode of action cannot be excluded for furan-induced tumor formation. Furan is metabolized by cytochrome P450 (CYP) enzymes, predominantly CYP2E1, to its major metabolite cis-2-butene-1,4-dial (BDA, maleic dialdehyde), a highly reactive electrophile identified as the key mediator of furan toxicity and carcinogenicity. Furan-mediated effects on glutathione (GSH) levels and cell viability can be suppressed by the CYP inhibitor 1-phenylimidazole and increased by pretreatment of rats with acetone (a CYP2E1-inducing agent), indicating that furan cytotoxicity depends on its metabolic activation. BDA has been shown to react with cellular nucleophiles such as GSH and amino acids and to cause cross-links between thiols and amino groups, giving rise to lactam and pyrrole derivatives. Furan reduced the percentage of DNA in the comet tail in turkey liver fetal hepatocytes. Furan was also shown to induce chromosomal aberrations and sister chromatid exchanges (SCEs) in Chinese hamster ovary (CHO) cells. A statistically significant increase of micronucleated cells was recently reported in the spleen of furan-treated mice. A reduction of percentage of DNA in comet tail in liver cells was observed following treatment of turkey fetuses in ovo. Exposure to furan at doses associated with increased tumor incidences initially causes hepatocellular necrosis, accompanied by inflammation and sustained regenerative proliferation of hepatocytes, which may present key events in furan-induced hepatocellular carcinogenicity. Subcapsular and centrilobular necrosis accompanied by markedly increased liver enzymes is the primary response to furan treatment. The involvement of inflammatory processes in furan toxicity is also reflected by increased expression of cytokines and other inflammation-associated genes, such as IFN-γ, IL-1β, IL-6, IL-10, and components of the complement system, which may, however, also derive from lesions involving the biliary tract. Indeed, increased production of reactive oxygen species in response to furan is suggested by immunohistochemical detection of 8-oxo-dG within nuclei of hepatocytes of centrilobular areas following high-dose exposure and changes in the expression of genes responsive to oxidative stress in rats and/or mice. (1)
MetabolismNot Available
Toxicity ValuesNot Available
Lethal DoseNot Available
Carcinogenicity (IARC Classification)2B, possibly carcinogenic to humans. (2)
Uses/SourcesNot Available
Minimum Risk LevelNot Available
Health EffectsNot Available
SymptomsNot Available
TreatmentNot Available
Normal Concentrations
Not Available
Abnormal Concentrations
Not Available
DrugBank IDNot Available
HMDB IDHMDB13785
PubChem Compound ID8029
ChEMBL IDCHEMBL278980
ChemSpider ID7738
KEGG IDC14275
UniProt IDNot Available
OMIM ID
ChEBI ID35559
BioCyc IDNot Available
CTD IDNot Available
Stitch IDNot Available
PDB IDSUC
ACToR IDNot Available
Wikipedia LinkFuran
References
Synthesis ReferenceNot Available
MSDSLink
General References
  1. Moro S, Chipman JK, Wegener JW, Hamberger C, Dekant W, Mally A: Furan in heat-treated foods: formation, exposure, toxicity, and aspects of risk assessment. Mol Nutr Food Res. 2012 Aug;56(8):1197-211. doi: 10.1002/mnfr.201200093. Epub 2012 May 29. [22641279 ]
  2. International Agency for Research on Cancer (2014). IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. [Link]
Gene Regulation
Up-Regulated GenesNot Available
Down-Regulated GenesNot Available

Targets

General Function:
Steroid hydroxylase activity
Specific Function:
Metabolizes several precarcinogens, drugs, and solvents to reactive metabolites. Inactivates a number of drugs and xenobiotics and also bioactivates many xenobiotic substrates to their hepatotoxic or carcinogenic forms.
Gene Name:
CYP2E1
Uniprot ID:
P05181
Molecular Weight:
56848.42 Da
2. DNA
General Function:
Used for biological information storage.
Specific Function:
DNA contains the instructions needed for an organism to develop, survive and reproduce.
Molecular Weight:
2.15 x 1012 Da