2-Amino-6-chloro-3,5-dicyanopyrazine

The conversion of DAMN into 2,3-dicyanopyrazines substituted in the 5-and 6-positions with various combinations of amino, cyano, chloro, and hydroxyl groups will be described in this section along with transformations of these initially formed materials into a variety of other multifunctional and fused ring pyrazines. 

Q-(p-Toluenesulfonyloxyiinino)malononitrile (104), when treated with malono-nitrile in basic conditions, has been shown to give salts of l,l,3,3-tetracyano-2-azapropenide (105), which with concentrated sulfuric acid in methanol gave 2-amino-3,5-dicyano-6-methoxypyrazine (106) (484) and with hydrochloric acid in acetone gave 2-amino-6-chloro-3,5-dicyanopyrazine (485, 486). Catalytic cyclization of 2-(2 -aminobutylamino)butanol with Raney nickel has been found to give a mixture of 2,5-diethylpiperazine (25% yield) and 2,5-diethylpyrazine (8%) (487). 

Other alkoxy dechlorinations were 2-chloro-5-ethoxy-3,6-dimethylpyrazine (872) and 2-amino-6-chloro-3,5-dicyanopyrazine (484) with ethoxide ion 5-chloro-... 

Dicyanopyrazine with sodium methoxide in methanol with ammonia at reflux gave 5,7-diimino-6//-pyrrolo[3,4-i)]pyrazine (65) (1442) and 2,3-dicyano-5,6-dimethyl(and 5,6-diphenyl)pyrazine with hydrazine by the procedure of Patel and Castle (1339) gave 2,3-dimethyl(and 2,3-diphenyl)-5,8-diaminopyrazino[2,3-rfJ-pyridazine(s) (66) (1435). Fusion of 2-chloro-3-cyano-5,6-diphenylpyrazine with urea and thiourea was reported to give 4-amino-2-hydroxy(and mercapto)-6,7-diphenylpteridine (848). 

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