DISN

Methyl Criegee biradical (CH3(H)C60 ) MCRG Dinitrate of isoprene DISN... 

Aldehydes condense with DISN to give 2-alkylimidazoles, but in low yield (73USP37099(X)). A related reaction with ketones produces 2,2-dialkyl-4,5-dicyano-2//-imidazoles. When one alkyl group is methyl and the other is a... 

V. Pyrazines from Diaminomalonitrile (DAMN) and/or Diiminosuccinonitrile (DISN)... 

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

Nucleophiles attack DISN at the imine carbon with subsequent loss of either ammonia or hydrogen cyanide (72JOC4136). Neutral or basic conditions favor the loss of cyanide ion. A small amount of a strong acid catalyzes the addition, after which cyanide is lost. However strong acids not only catalyze the reaction, but when they are present in larger amounts, they can... 

Although o-phenylenediamine and DISN react under neutral conditions to give a low yield of 2,3-diaminoquinoxaline, DAMN and DISN do not react at all under these eonditions and at elevated temperatures gross mixtures are obtained. Weakly basic or acidic catalysts promote the condensation, but the acyclic products 51 and 52 dominate the mixtures which usually result (Scheme 21) (74JOC1235). 

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),... 

DISN reacts with the electron-rich olefins 112 and 113 with complete retention of stereochemistry to give the 1,2,3,4-tetrahydropyrazines 114 and 115, respectively. Heat or acid converts either isomer to 2,3-dicyanopyrazine (116) (Scheme 40). 

When DISN reacts with electron-rich styrenes such as p-methoxystyrene, good yields of reduced pyrazines 117, often accompanied by their oxidized forms, are obtained. However, reaction with electron-deficient styrenes like p-fluorostyrene give the 2-amino-3-(2-arylaziridin-l-yl)maleonitriles (118) (72JA3242 84JOC813). 

Ynamines 119 and 120 give pyrazines 121 and 122 directly upon reaction with DISN (Scheme 41). 

Cyclopentadiene reacts slowly with DISN giving 123, which, although resistant to oxidation to the diazaindene 124, can be converted to the pyrazine 125 by a reduction/oxidation sequence. Attempts to oxidize 125 to 124 were also unsuccessful (84JOC813) (Scheme 42). 

DAMN plus SClj or thionyl chloride gives 3,4-dicyano-l,2,5-thiadiazole (143) (61USP2990408 61USP2990409 77GEP(O)2651604). DISN plus SCl ... 

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