Pyrazine

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Pyrazine
Pyrazine molecule
Pyrazine molecule
Names
Preferred IUPAC name
Pyrazine[1]
Other names
1,4-Diazabenzene, p-Diazine, 1,4-Diazine, Paradiazine, Piazine, UN 1325
Identifiers
3D model (
JSmol
)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
100.005.480 Edit this at Wikidata
EC Number
  • 206-027-6
UNII
  • InChI=1S/C4H4N2/c1-2-6-4-3-5-1/h1-4H checkY
    Key: KYQCOXFCLRTKLS-UHFFFAOYSA-N checkY
  • InChI=1/C4H4N2/c1-2-6-4-3-5-1/h1-4H
  • c1cnccn1
Properties
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)
Soluble
Acidity (pKa) 0.37[2] (protonated pyrazine)
-37.6·10−6 cm3/mol
Hazards
GHS labelling:
GHS05: CorrosiveGHS07: Exclamation mark
Danger
H228, H315, H319, H335
P210, P261, P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
2
0
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).
checkY verify (what is checkY☒N ?)

Pyrazine is a

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

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),

selfcondensation, but differing in the way the alpha-ketoamine is synthesised.[6][7]

Gutknecht pyrazine synthesis

The Gastaldi synthesis (1921) is another variation:[8][9]

Gastaldi synthesis

See also

References

  1. .
  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". www.chemspider.com. Retrieved 4 January 2022.
  4. PMID 12650854
    .
  5. Berichte der deutschen chemischen Gesellschaft
    Volume 9, Issue 1, pp. 563–564, 1876
  6. ^ G. Gastaldi, Gazz. Chim. Ital. 51, (1921) 233

External links