Imidazo triazines, formation

The interaction of perfluoro-5-azanon-4-ene with amidines and 2-amino-benzimidazole occurs with formation of a six-membered heterocycle, giving 2,4-bis(heptafluoropropyl)-6-phenyl-[l,3,5]triazine, 2,4-bis(hep-tafhioropropyl)-6-methyl-[l,3,5]triazine, and a tricyclic compound—2,4-bis(heptafhioropropyl)benz-[4,5]imidazo[l,2-tf][l,3,5]triazine (01IZY457). 

Bromination of enamine ketone 792 leads to the formation of 793 (Scheme 197). The Br in 793 can be replaced with hydrazine to give 2-(l-hydrazino-l,2-oxopropylidene)imidazoline 794. Cyclization between the nitrogen termini in 810 with aldehyde or acid chlorides affords 795, imidazo[2,T [l,2,4]triazine 796 and imidazo[2,Tr/ [l,2,4]triaze-pines 797 and 798, respectively <1997SC2433>. 

Formation of imidazo[4,5-e]-1,2,4-triazines 119 has been observed to occur when 6-ethylamino-5-methylamino-1,2,4-triazines 118 react with benzamidine. However, in this case only the methylamino group at C-5 is substituted by the amidine, while the ethylamino group at C-6 participates itself as a nucleophile in an intramolecular cyclization reaction (Scheme 68) (78CPB3154). 

A special type of modification of substituents bound to the 1,2,4-triazine nucleus is the formation of condensed 1,2,4-triazines, such as formation of imidazo[4,5-c]-l,2,4-triazines 21 by reaction of 1,2,4-triazine-5,6-diamines with ortho esters 103-189 with glyoxal or substituted glyoxals dihydro- and tetrahydropyrazino[2,3-e]-l, 2,4-triazines 22 are obtained. Pyrazino[2,3-e]-1,2,4-triazine 23 is synthesized by dehydration of the tetrahydropyrazino[2,3-< ]-l,2,4-tri-azine.293-297-301... 

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