Synthesis and mechanism of formation of novel 2,5‐dihydro‐2,5‐diimino‐3,4‐di[(N,N‐dimethylamino)methylideneamino]pyrroles and 5‐amino‐3,4‐di[(N,N‐dimethylamino)methylideneamino]‐2H‐2‐iminopyrroles

Abstract

Formation of 5‐amino‐3,4‐di[(N,N‐dimethylarnino)methylidenearnino]‐2H‐2‐iminopyrroles 3 from the reaction of (Z)‐N1‐(2‐amino‐1,2‐dicyanovinyl)‐N2‐substituted‐formamidines 1 with dimethylformamide diethyl acetal has been shown to occur by initial formation of (Z)‐N1‐{l,2‐dicyano‐2‐[N,N‐dimethylamino)methylideneamino]vinyl}formamidines 8 (isolated), followed by base catalysed cyclisation and imi dazole ring opening by dimethyl amine. The kinetic product of the ring opening reaction is the 2,5‐diimino2,5‐dihydropyrrole derivatives 11, which have been isolated and characterized spectroscopically and by a single crystal X‐ray analysis on the R = Ph derivative. In solution at room temperature the N‐aryl derivatives undergo a rapid Dimroth rearrangement to give the thermodynamic ally more stable isomer 3, but compound 11 (R = Me) is much more stable in solution.

The Reactions of Diaminomaleonitrile with Isocyanates and Either Aldehydes or Ketones Revisited

“…Diaminomaleonitrile (DAMN, 1 ), a tetramer of hydrogen cyanide, is a versatile precursor to a number of nitrogen heterocycles, which include imidazoles and purines, pyrroles, pyrimidines, pyrazines, diazepines, 1b, and triazepines …”

Regioselective Synthesis of 2-Aryl-5-cyano-1-(2-hydroxyaryl)-1H-imidazole-4-carboxamides Self-Assisted by a 2-Hydroxyaryl Group

“…Diaminomaleonitrile (DAMN) is a versatile building block in organic synthesis, extensively used as a precursor in the preparation of a large variety of nitrogen heterocycles, including pyrimidines, pyrazines, , purines, − adenines, imidazoles, , and pyrroles, , among others. The synthetic scheme to achieve these compounds usually involves the modification of one of the amino groups in DAMN by the reaction with aldehydes, orthoformate, acid chlorides, acid anhydrides, or isocyanates, followed by an intramolecular condensation reaction .…”

Programmed Formation of HCN Oligomers through Organosulfur Catalysis

“…Diaminomaleonitrile (DAMN, 1 ), an interesting product formed during HCN oligomerization, has been heavily studied as a common precursor to a variety of biologically relevant and commercially useful heterocycles (e.g., imidazoles, pyrroles, pyrazines, amino acids, see Scheme ) during the past decades . For instance, DAMN is a key element in the abiotic formation of purines and pyrimidines (nucleobases) as well as in the prebiotic formation of more complex organic molecules …”