Diaminomaleonitrile

Many variants of this procedure exist. Thus, Kano and coworkers have carried out the condensation of /3-keto sulfoxides with diaminomaleonitrile (Scheme 36) (78S372). This reaction probably yields an intermediate dihydropyrazine which is oxidized under the reaction conditions, and it seems likely that the condensation of the carbonyl group and the amine is the first step. 

Diaminomaleonitrile (1) condenses with acetylacetone to give the 6//-l,4-diazepine 2.186 The reaction does not succeed with dibenzoylmethane or /J-oxo esters. 

The dihydrodiazepine 3 obtained from diaminomaleonitrile and A. A -dimethylacrylamide is dehydrogenated to the diazepine 4 by 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ).186... 

Substituting benzene-1,2-diamine by diaminomaleonitrile gives an analogous product 13 in this case the cyclobutaquinoxalinc intermediate could not be isolated.35... 

The photocyclization of cis-diaminomaleonitrile (372) to 4-amino-5-cyanoimidazole (373) has been shown to proceed via the trans isomer 374.308 4-Amino-3-cyanopyrazole does not seem to be an intermediate in this transformation.309 Analogous cyclizations have been reported in the imidazole 373 which undergoes further photoreaction to yield the bicycle 375, and in o-aminobenzonitrile which is converted into indazole.310 This photocyclization has been extended to include enaminonitriles 376 spectroscopic evidence for the intermediacy of iminoketenimes 377 in this311 and other similar transformations312 have been reported. 

The diaminomaleonitrile derivative 186 is transformed into 187 by treatment with triethyl orthoacetate (Equation 27) <2006S3437>. Other orthoesters react similarly. 

Shaabani et al. developed a one-pot MCR for the synthesis of 1,6 dihydropyrazine derivatives from condensation reactions among diketene 42, an isocyanide 40, and 2,3-diaminomaleonitrile 41 (Scheme 7) [27]. 

The synthesis of olmesartan medoxomil (5) by the Sankyo Company is illustrated in Scheme 9.8. Heating of diaminomaleonitrile (34) with trimethylorthobutyrate provided imidazole-4,5-dicarbonitrile 35, which underwent hydrolysis to the dicarboxylic acid followed by esterification to give imidazole diester 36. Addition of methyl magnesium... 

Diaminomaleonitrile (DAMN) 133, a tetramer of hydrogen cyanide, is an important precursor for the synthesis of pyrazine-2,3-dicarbonitriles 134 (Scheme 36 Table 2). The condensation with a-diketones proceeds at room temperature or by warming for a short time. 

A poly(phenylquinoxaline) was prepared for electroluminescence applications <1996SM(76)105>. Crystallization of solution donor-acceptor complexes of 2,3-dimethylquinoxaline 1,4-dioxide or phenazine 5,10-dioxide with TCNE afforded two-component solids containing weakly bound 1-D donor-acceptor arrays <1997TL7665>. A pyrazine ladder polymer was constructed from two different pyrazine units, as an optical device <1999JA8783>. The new electron-deficient macrocycle tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine was prepared from l,2-di(2-pyridyl)ethanedione and 2,3-diaminomaleonitrile for a study of its electrochemical properties <2004IC8626>. 

Four tetramers of hydrogen cyanide have been isolated the well-known diaminomaleonitrile (DAMN), diaminofumaronitrile, 4-amino-5-cyano-imidazole, and an HCN adduct of s-triazine. 

Ferris and Antonucci73 have reported a photochemical synthesis of imidazo[4,5-d]imidazole (80) from 4-aminoimidazole-5-carbonitrile (78), which has attracted interest since 78, and its photochemical precursor diaminomaleonitrile (77) have been proposed74 as key intermediates in the prebiotic chemical evolution of purines. Mechanistic studies7311 suggest that the fused pyrazole 79 may be an intermediate. 

Oxidative cyclizations of Schiff bases (179) of 1,2-diaminomaleonitrile are conveniently accomplished using NCS under basic conditions (84S1057). 

In a similar reaction it is also reported that 4,8-diaminopyrimido[5,4-d]pyrimidine is formed in the reaction of hydrogen cyanide with liquid ammonia. This reaction also presumably proceeds by way of the hydrogen cyanide tetramer, diaminomaleonitrile... 

Four mechanisms have been advanced for the prebiotic formation of amino acids. The first involves a cyanohydrin (reaction 2) and a related route (reaction 3) can be invoked to account for the presence of hydroxy acids. These particular reactions have been studied in considerable detail both kinetically and in terms of thermodynamic quantities.347 An alternative route (4) involves the hydrolysis of a-aminonitriles, which are themselves formed directly in anhydrous CH4/NH3 mixtures.344 Cyanoacetylene, formed in CH4/N2 irradiations,349 yields significant amounts of asparagine and aspartic acids (reaction 5). Finally, a number of workers336,350"354 have proposed that HCN oligomers, especially the trimer aminoacetonitrile and the tetramer diaminomaleonitrile, could have been important precursors for amino acid synthesis. Reaction mixtures involving such species have yielded up to 12 amino acids. Table 11 indicates the range of amino acids produced in these kinds of sparking syntheses. Of some interest is the fact that close parallels between these kinds of experiments and amino acid contents of carbonaceous chondrite meteorites exist.331,355,356... 

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