Pyrazine

Quality 0.50 · 1 view · Updated 2 months ago

Chemical compound

title: "Pyrazine" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["pyrazines", "simple-aromatic-rings"] description: "Chemical compound" topic_path: "general/pyrazines" source: "https://en.wikipedia.org/wiki/Pyrazine" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Chemical compound ::

| Watchedfields = changed | verifiedrevid = 417947419 | ImageFileL1 = Pyrazine 2D aromatic full.svg | ImageFileR1 = Pyrazine 2D numbers.svg | ImageFileL2 = Pyrazine-3D-balls-2.png | ImageAltL2 = Pyrazine molecule | ImageFileR2 = Pyrazine-3D-spacefill.png | ImageAltR2 = Pyrazine molecule | PIN = Pyrazine | OtherNames = 1,4-Diazabenzene, p-Diazine, 1,4-Diazine, Paradiazine, Piazine, UN 1325 |Section1={{Chembox Identifiers | ChemSpiderID_Ref = | ChemSpiderID = 8904 | ChEMBL_Ref = | ChEMBL = 15797 | StdInChI_Ref = | StdInChI = 1S/C4H4N2/c1-2-6-4-3-5-1/h1-4H | StdInChIKey_Ref = | StdInChIKey = KYQCOXFCLRTKLS-UHFFFAOYSA-N | CASNo_Ref = | CASNo = 290-37-9 | UNII_Ref = | UNII = 2JKE371789 | EINECS = 206-027-6 | PubChem = 9261 | SMILES = c1cnccn1 | InChI = 1/C4H4N2/c1-2-6-4-3-5-1/h1-4H | ChEBI_Ref = | ChEBI = 30953 |Section2={{Chembox Properties | Formula = C4H4N2 | MolarMass = 80.09 g/mol | Appearance = White crystals | Density = 1.031 g/cm3 | MeltingPtC = 52 | BoilingPtC = 115 | Solubility = Soluble | pKa =0.37 (protonated pyrazine) | MagSus = −37.6·10−6 cm3/mol |Section3={{Chembox Hazards | MainHazards = | FlashPtC = 55 | FlashPt_notes = c.c. | AutoignitionPt = | NFPA-H = 2 | NFPA-F = 2 | NFPA-R = 0 | NFPA-S = | GHSPictograms = | GHSSignalWord = Danger | HPhrases = | PPhrases =

Pyrazine is a heterocyclic aromatic organic compound with the chemical formula C4H4N2. It is a symmetrical molecule with point group D2h. Pyrazine is less basic than pyridine, pyridazine and pyrimidine. It is a "deliquescent crystal or wax-like solid with a pungent, sweet, corn-like, nutty odour".

Pyrazine and a variety of alkylpyrazines are flavor and aroma compounds found in baked and roasted goods. Tetramethylpyrazine (also known as ligustrazine) is reported to scavenge superoxide anions and decrease nitric oxide production in human granulocytes.

Synthesis

Many methods exist for the organic synthesis of pyrazine and its derivatives. Some of these are among the oldest synthesis reactions still in use.

In the Staedel–Rugheimer pyrazine synthesis (1876), 2-chloroacetophenone is reacted with ammonia to the amino ketone, then condensed and then oxidized to a pyrazine. A variation is the Gutknecht pyrazine synthesis (1879) also based on this selfcondensation, but differing in the way the alpha-ketoamine is synthesised.

:[[File:Gutknecht Pyrazine Synthesis.svg|500px|Gutknecht pyrazine synthesis]]

The Gastaldi synthesis (1921) is another variation:

:[[File:GastaldiSynthesis.svg|400px|Gastaldi synthesis]]

References

References

  1. [[International Union of Pure and Applied Chemistry]]. (2014). "Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013". [[Royal Society of Chemistry.
  2. Brown, H.C., et al., in Baude, E.A. and Nachod, F.C., ''Determination of Organic Structures by Physical Methods'', Academic Press, New York, 1955.
  3. "Pyrazine {{!}} C4H4N2 {{!}} ChemSpider".
  4. (2003). "Tetramethylpyrazine scavenges superoxide anion and decreases nitric oxide production in human polymorphonuclear leukocytes". Life Sciences.
  5. (1876). "Ueber die Einwirkung von Ammoniak auf Chloracetylbenzol". Berichte der Deutschen Chemischen Gesellschaft.
  6. (1879). "Ueber Nitrosoäthylmethylketon". Berichte der Deutschen Chemischen Gesellschaft.
  7. ''Heterocyclic chemistry'' T.L. Gilchrist {{ISBN. 0-582-01421-2
  8. G. Gastaldi, Gazz. Chim. Ital. 51, ('''1921''') 233
  9. ''Amines: Synthesis, Properties and Applications'' Stephen A. Lawrence 2004 Cambridge University Press {{ISBN. 0-521-78284-8

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

pyrazinessimple-aromatic-rings