With diiminosuccinonitrile

The preparation of some 2,3-dihydropyrazines from a, -dicarbonyl compounds with a,0-diamino compounds has been recorded in Section 11.2 (330, 330a, 331, 333, 334, 338-344, 349, 356, 357), with further data given in references 6, 337, 345, and 1547-1549. In addition hexamethyl-2,3-dihydropyrazine (16) has been prepared from 2,3-diamino-2,3-dimethylbutane and butane-2,3-dione (1550). Condensation of oxalyl chloride with diiminosuccinonitrile (10) in ether has been shown to give 2,3-dichloro-2,3-dicyano-5,6-dihydroxy-2,3-dihydropyrazine (17) (383). 

Diiminosuccinonitrile reacts with sulfur dichloride in dichloromethane at room temperature to give 1,2,5-thiadiazole-3,4-dicarbonitrile 226 in 93% yield <1972JOC4136>. The addition of catalytic naked chloride to the reaction mixture gave the bi-l,2,5-thiadiazole 227 <1991CB1517>. No experimental data were given for this transformation, but it was shown that the bi-l,2,5-thiadiazole 227 can be formed directly from dicyanothiadiazole 226 under analogous reaction conditions (Equation 53) <1991CB1517>. 

An acyclic NCCN system in which the N-C links may be sp, sp2 or sp3 hybridized reacts with sulfur monochloride or sulfur dichloride to form the appropriate 1,2,5-thiadiazole (68AHC(9)107, 67JOC2823). Thus, diiminosuccinonitrile (384) gives 3,4-dicyano-l,2,5-thiadiazole (385) (72JOC4136). Tables 16 and 17 in CHEC 4.26 list the various substituted systems prepared in this fashion. 

A A -Oxazolines (122) has been obtained from the acid-catalyzed reaction of diiminosuccinonitrile with HFA (20). 

A select group of 1,4-diaza-1,3-butadienes have been demonstrated to participate as 4ir components of Diels-Alder reactions (Table 12). Perhaps the most successful system described to date is the LUMOdiene-controlled [4 + 2] cycloaddition reaction of diiminosuccinonitrile, a 1,4-diaza-1,3-butadiene substituted with C-2 and C-3 electron-withdrawing groups, with electron-rich dienophiles (equation 15). A common and competitive reaction of the a-diimines is [2 + 2] cycloaddition to afford azetidine cycloaddition products and many of the early reports of the [4 + 2] cycloaddition reactions are incorrect. 

Condensation of diiminosuccinonitrile (10) with 3-methylbutan-2-one gave 5,6-dicyano-2,2,3-trimethyl-l,2-dihydropyrazine (II) (11%) and 4,5-dicyano-l-isopropyl-2-methylimidazole (7.6%) (383). Cyclization of a-cyanoalkyldiamino-maleonitiiles (12, e.g., R = Me) with phosphorus pentoxide in refluxing ethanol has been shown to give 5,6-dicyano-3-hydroxy(-2-substituted)-l, 2-dihydropyrazines(I3, e.g., R = Me) (489, 490) and the conversion of benzylidenediaminomaleonitrile to 5-carbamoyl-6-cyano- and 6-carbamoyl-5-cyano-2,3-diphenyl-l, 2-dihydropyrazines has been described in Section II.3 (395a). 

Diiminosuccinonitrile (DISN) (10) reacts exothermically with ds-l,2-dimethoxy-ethylene (62) in acetonitrile to give 5,6-dicyano-2,3-dimethoxy-l,2,3,4-tetrahydro-pyrazine (63) (386, 1596). Styrene and p-halogenostyrenes reacted with DISN in acetonitrile at room temperature to form 2-amino-3-(2 -arylaziridin-r-yl)maleonitrile (64) (50-80%), whereas the more electron-rich p-methoxystyrene and 2-vinylfuran gave 5-aryl-2,3-dicyano-l,4,5,6-tetrahydropyrazine(65)(60-80%).p-Methylstyrene gave both types of products (1597). 

Reaction of diiminosuccinonitrile (10) with oxalyl chloride (ClOCCOCi) afforded... 

Diiminosuccinonitrile reacts with oxalyl chloride to form 5,6-dichloro-S,6-dicyanopiperazine-2,3-dione (383) and 2,6-dibenzyloxypyrazine was reduced with hydrogen over palladium-charcoal to piperazine-2,6-dione (832). 

Diiminosuccinonitrile reacts with trifluoracetic anhydride to give 2/f-imidazoles <9iCBi5i7>. (b) Formation of the 1,5- and 4,5-bonds (Scheme 153) ... 

Diiminosuccinonitrile readily participates in [4 + 2] cycloadditions with electron-rich olefins [Eq. (58)].140... 

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