2,3-Diaminomaleonitrile: A Multifaceted Synthon in Organic Synthesis.

2,3-Diaminomaleonitrile (DAMN), a tetramer of hydrogen cyanide, displays weakly basic properties and has reactivity comparable to o-phenylenediamine. It has emerged as a versatile, cheap as well as a readily accessible building block towards the synthesis of a variety of organic compounds. The present review focuses on the applications of 2,3-diaminomaleonitrile for the synthesis of Schiff's base, imidazoles, pyrazines, quinoxolines, benzodiazocines, 1,4-diazepines, purines, pyrimidines, pyrazine-tetrazole hybrids, triazoles, thiadiazole, thiazolidines, porphyrazines, formamidines, 1,3,5-triazepines, pyrrolo[3,4-b][1,4]diazepin-6(3H)-ones, triaza[22]annulenes, pyrrolo[3,4-f][1,3,5]triazepines, spiro compounds, pyrazoles and 2,3-dicyano-5,7- bismethylthieno[3,4-b]pyrazine.