Dioxo-5,6-dicyano-l,2,3,4-tetrahydropyrazine

Condensation of DAMN with Oxalyl Chloride 1. 2,3-Dioxo-5,6-dicyano-l,2,3.4-tetrahydropyrazine 

Preparation of 2,3-dioxo-5,6-dicyano-l,2,3,4-tetrahydropyrazine (67) by condensation of DAMN with oxalyl cyanide or oxalyl chloride, and by reaction of DISN with oxalyl chloride, followed by the treatment of the intermediate with ethanethiol, was noted in Section V,B,1. 

Procedures have been reported to convert 67 into the corresponding imide (74) (73USP3736299), dicarboxylic acid (75), anhydride (76), and a variety of acid/esters (77) and diesters (78) (75USP3915974). Chromic acid oxidation of 2,3-dichloroquinoxaline has also been reported as a route to 75 (58RTC842). 

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