DAMN with DISN

A. Condensation of DAMN with DISN 1. General Considerations... 

The condensation of DAMN with 1,2-diimino-l, 2-dimethoxyethane (70) gives 2-amino-5,6-dicyano-3-methoxypyrazine (71) (385), but as in the condensation of DAMN with DISN the control of acid concentration is critical. The condensation of DAMN with chloroacetone or pyruvaldehyde has been shown to give 23-dicyano-5-methylpyrazine (385) and DAMN with methylsulfinylmethyl phenyl ketone refluxed in ethanol gave 23-dicyano-5-phenylpyrazine (386a). A, 7V -Dichlorodi-iminosuccinonitrile (a2DISN) (72) reacts with some olefins to give pyrazines. Thus with styrene (73, R = Ph, R = H) in benzene it gave 23-dicyano-5-phenyl-pyrazine (74, R = Ph, R = H). Similar reactions were observed with /J-methyl-styrene and 23-dihydropyran (387). 

Compound 67 has also been prepared by (1) reaction of DAMN with oxalyl chloride (56LA95) and (2) by reaction of DISN with oxalyl chloride, followed by treatment with ethanethiol (72JOC4136). 

Although 69 has never been isolated and characterized, it is believed to be formed when a solution of DISN is treated with 1 equivalent of p-toluenesulfonic acid monohydrate. Addition of DAMN to this solution produces a moderate yield of the pyrazines 57 and 70 by the loss of 1 mol hydrogen cyanide plus 1 mol water in the first case, and by the loss of 2 mol hydrogen cyanide in the second case (Scheme 28). Small amounts of the two... 

Treatment of 2-amino-3,5,6-tricyanopyrazine (57), prepared in 95% yield by condensation of DISN and DAMN (Section V,A,2,b), with ammonia under very mild conditions gives 2,6-diamino-3,5-dicyanopyrazine (58) in nearly quantitative yield (74USP3814757). The regiochemistry of the displacement was determined by hydrolysis to 2,6-diamino-3,5-dicarboxypyrazine (85),... 

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