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Pyrazine chemical structure.png
IUPAC name Pyrazine
Other names 1,4-Diazabenzene, p-Diazine, 1,4-Diazine, Paradiazine, Piazine, UN 1325
CAS number 290-37-9
PubChem 9261
EINECS number 206-027-6
ChEBI 30953
InChI InChI=1/C4H4N2/c1-2-6-4-3-5-1/h1-4H
Molecular formula C4H4N2
Molar mass 80.09 g/mol
Appearance White crystals
Density 1.031 g/cm3
Melting point

52 ºC

Boiling point

115 ºC

Solubility in water Soluble
NFPA 704

NFPA 704.svg

R-phrases R11, R36/37/38
S-phrases S16, S26, S36
Flash point 55 ºC c.c.
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

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Pyrazine is a heterocyclic aromatic organic compound.

Pyrazine is a symmetrical molecule with point group D2h. It is found in folic acid in the form of pterin. Derivatives like Phenazine are well known for their antitumor, antibiotic and diuretic activity. Pyrazine is less basic in nature than pyridine, pyridazine and pyrimidine. Tetramethylpyrazine is reported to scavenge superoxide anion and decrease nitric oxide production in human polymorphonuclear leukocytes[1]. It is also found on the cigarette additives list.


Many methods exist for the organic synthesis of pyrazine and derivatives and some of them very old.

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 [2] A variation is the Gutknecht Pyrazine Synthesis (1879) also based on this selfcondensation but differing in the way the alpha-ketoamine is synthesised (the chlorine compound in the above method is a lachrymatory agent) [3] [4]

Gutknecht Pyrazine Synthesis

The Gastaldi synthesis (1921) is another variation [5] [6]:

Gastaldi synthesis

See also

External links


  1. Life Sciences, 2003, 72, 2465-2472, DOI:
  2. Ueber die Einwirkung von Ammoniak auf Chloracetylbenzol (p 563-564) W. Staedel, L. Rügheimer doi:10.1002/cber.187600901174 Berichte der deutschen chemischen Gesellschaft Volume 9, Issue 1 , Pages 563 - 564 1876
  3. Mittheilungen Ueber Nitrosoäthylmethylketon H. Gutknecht Berichte der deutschen chemischen Gesellschaft Volume 12, Issue 2 , Pages 2290 - 2292 1879 doi:10.1002/cber.187901202284
  4. Heterocyclic chemistry T.L. Gilchrist ISBN 0-582-01421-2
  5. G. Gastaldi, Gazz. Chim. Ital. 51, (1921) 233
  6. Amines: Synthesis, Properties and Applications Stephen A. Lawrence 2004 Cambridge University Press ISBN 0521782848

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