2.4- Diaza-l,3-diene groups

Diaminomethylene compds. 2,4-Diaza-l,3-diene groups Enazo compds. Ene-l,2 diamines Enediazonium salts Enehydrazines... 

Tetrahydro-2H-thiazolo[3,2-a]-s-triazin-4-ones from 2,4-diaza-l,3-diene groups and isocyanates... 

Diaminomefiiylene compds. 2,4-Diaza-l,3-diene groups Enazo compds. 

An investigation concerning intramolecular aza Diels-Alder reactions of 3-(co-alkynyl)-l,2,4-triazines has been published by Taylor et al. [327] and trichloro-1,2,4-triazine has been introduced as novel triazine diene recently [328]. 1,2,4-Triazines are a useful alternative of 1,4-diaza-l,3-butadienes with regard to the aforementioned synthesis of pyrazines since Taylor s group has found them to undergo cycloadditions with nitriles followed by extrusion of nitrogen [329]. This reaction is noteworthy since it is a Diels-Alder reaction of both electron-deficient diene and dienophile. 

Amino-acul complexes. frans-(0,X)-[CoX(aminoacidato)(dien)]Y (X == CN, NO2, or Cl Y = Br, Cl, or ClO aminoacid === Gly, a-aminobutyric acid, L-Ala. L-Val, L-Thr, or L-Pro) complexes have been isolated. The cyano-complexes were shown to exist in the new conformational isomeric endo- and cxo-forms. This refers to the position of the hydrogen atom bonded to the central N of dien w ith respect to the cyanide group. The tetramine ligands 1,3-diaminopropane, 3,7-diaza-l,9-nonanediamine (2,3,2-tet), and 4,7-diaza-1.10-decanediamine (2,2,3-tet) exhibit marked topological specificity in the complexes [Co(tetramine)(aa)] (aa = Gly. Ala, Val. or Sar). Thus a-[Co-(3,2,3-tet)aa] and P2-[Co(2,3,2-tet)aa] appear to be formed exclusively under the synthetic conditions employed. 

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