Other names 1,4-Diazabenzene, p-Diazine, 1,4-Diazine, Paradiazine, Piazine, UN 1325
Identifiers
CAS Number
290-37-9Y
3D model (JSmol)
Interactive image
ChEBI
CHEBI:30953Y
ChEMBL
ChEMBL15797Y
ChemSpider
8904Y
ECHA InfoCard
100.005.480
EC Number
206-027-6
PubChem CID
9261
UNII
2JKE371789Y
CompTox Dashboard (EPA)
DTXSID8049410
InChI
InChI=1S/C4H4N2/c1-2-6-4-3-5-1/h1-4H YKey: KYQCOXFCLRTKLS-UHFFFAOYSA-N Y
InChI=1/C4H4N2/c1-2-6-4-3-5-1/h1-4H
SMILES
c1cnccn1
Properties
Chemical formula
C4H4N2
Molar mass
80.09 g/mol
Appearance
White crystals
Density
1.031 g/cm3
Melting point
52 °C (126 °F; 325 K)
Boiling point
115 °C (239 °F; 388 K)
Solubility in water
Soluble
Acidity (pKa)
0.37[2] (protonated pyrazine)
Magnetic susceptibility (χ)
−37.6·10−6 cm3/mol
Hazards
GHS labelling:
Pictograms
Signal word
Danger
Hazard statements
H228, H315, H319, H335
Precautionary statements
P210, P261, P305+P351+P338
NFPA 704 (fire diamond)
220
Flash point
55 °C (131 °F; 328 K) c.c.
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Yverify (what is YN ?) Infobox references
Chemical compound
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".[3]
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.[4]
Synthesis
[edit]
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.[5] A variation is the Gutknecht pyrazine synthesis (1879) also based on this selfcondensation, but differing in the way the alpha-ketoamine is synthesised.[6][7]
The Gastaldi synthesis (1921) is another variation:[8][9]
See also
[edit]
Alkylpyrazines
Methoxypyrazines
Simple aromatic rings
Benzene, an analog without the nitrogen atoms
Pyridazine, an analog with the second nitrogen atom in position 2
Pyridine, an analog with only one nitrogen atom
Pyrimidine, an analog with the second nitrogen atom in position 3
Piperazine, the saturated analog
References
[edit]
^International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 141. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
^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.
^"Pyrazine | C4H4N2 | ChemSpider". www.chemspider.com. Retrieved 4 January 2022.
^Zhang, Zhaohui; Wei, Taotao; Hou, Jingwu; Li, Gengshan; Yu, Shaozu; Xin, Wenjuan (2003). "Tetramethylpyrazine scavenges superoxide anion and decreases nitric oxide production in human polymorphonuclear leukocytes". Life Sciences. 72 (22): 2465–2472. doi:10.1016/S0024-3205(03)00139-5. PMID 12650854.
^Staedel, W.; Rügheimer, L. (1876). "Ueber die Einwirkung von Ammoniak auf Chloracetylbenzol". Berichte der Deutschen Chemischen Gesellschaft. 9: 563–564. doi:10.1002/cber.187600901174.
^"Ueber Nitrosoäthylmethylketon". Berichte der Deutschen Chemischen Gesellschaft. 12 (2): 2290–2292. 1879. doi:10.1002/cber.187901202284.
^Heterocyclic chemistry T.L. Gilchrist ISBN 0-582-01421-2
^G. Gastaldi, Gazz. Chim. Ital. 51, (1921) 233
^Amines: Synthesis, Properties and Applications Stephen A. Lawrence 2004 Cambridge University Press ISBN 0-521-78284-8
External links
[edit]
Safety evaluation of food additives – pyrazine derivatives
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?) Infobox references 
