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|Section2= |Section3= }} Pyrazine is a heterocyclic aromatic organic compound with the chemical formula C4H4N2. Pyrazine is a symmetrical molecule with point group D2h. Derivatives such as phenazine are well known for their antitumor, antibiotic and diuretic activities. Pyrazine is less basic than pyridine, pyridazine and pyrimidine. Tetramethylpyrazine (also known as ligustrazine) is reported to scavenge superoxide anion and decrease nitric oxide production in human polymorphonuclear leukocytes, and is a component of some herbs in traditional Chinese medicine.〔http://www.itmonline.org/arts/ligustrazine.htm〕 ==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. 〔''Ueber die Einwirkung von Ammoniak auf Chloracetylbenzol'' (pp. 563–564) W. Staedel, L. Rügheimer Berichte der deutschen chemischen Gesellschaft Volume 9, Issue 1, pp. 563–564, 1876〕 A variation is the Gutknecht pyrazine synthesis (1879) also based on this selfcondensation, but differing in the way the alpha-ketoamine is synthesised 〔''Mittheilungen Ueber Nitrosoäthylmethylketon'' H. Gutknecht Berichte der deutschen chemischen Gesellschaft Volume 12, Issue 2 , pp. 2290–2292, 1879 〕〔''Heterocyclic chemistry'' T.L. Gilchrist ISBN 0-582-01421-2〕 : The Gastaldi synthesis (1921) is another variation:〔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〕 : 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「pyrazine」の詳細全文を読む スポンサード リンク
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