Characterization of new mesomeric betaines arising from methylation of imidazo[2,1-c][1,2,4]triazin-4(1H)-one, pyrazolo[5,1-c][1,2,4]triazin-4(1H)-one, and 1,2,4-triazolo[5,1-c][1,2,4]triazin-4(1H)-one

The synthesis of labeling azolo-1,2,4-triazines with 15N isotope in azole and azine parts

“…One general method for the synthesis of 1,2,4-triazolo [5,1-c] [1,2,4]triazines and related azolo fused 1,2,4-triazines is based on the reaction of diazoazoles with CH-active methylene compounds. The use of 15 N-labeled nitrous acid for diazotation of 2-aminoimidazole followed by coupling with Meldrum's acid results in imidazo [2,1-c] [1,2,4]triazinone containing 15 N isotope in azine cycle.…”

“…The use of 15 N-labeled nitrous acid for diazotation of 2-aminoimidazole followed by coupling with Meldrum's acid results in imidazo [2,1-c] [1,2,4]triazinone containing 15 N isotope in azine cycle. 1 So, diazoazoles 2a*,b* were obtained by treatment of 2-R-amino-1,2,4-triazole 1a,b with K 15 NO 2 (86% of label) under acidic conditions. Reaction of 2a*,b* with ethyl nitroacetate as active methylene compound in the presence of Na 2 CO 3 gave salts 4a*,b* (Scheme 1).…”

“…15 N Labeling of atom N(5) of 7-amino-6-phenyl-1,2,4-triazolo [5,1-c] [1,2,4]triazine (7a*) was achieved by reaction of 1,2,4-triazole derivative 2a* with α-formyl-α-phenylacetonitrile (Scheme 2). It should be noted that phenylacetonitrile itself did not interact with diazoazole 2a*.…”

“…[1][2][3][4] Incorporation of stable isotopes into the molecules of biological active compounds can be used in pharmacological studies on early phases of drug design [5][6][7][8] . It substitutes the use of radioactive isotopes and allows the investigation of drug metabolism to be carried out in humans.…”

“…It substitutes the use of radioactive isotopes and allows the investigation of drug metabolism to be carried out in humans. 5,8 The great interest in 1,2,4-triazolo [5,1-c] [1,2,4]triazinones and their sodium salts, along with azoloannelated 1,2,4-triazines, is due to their high activity against different kinds of viruses including influenza and bird flu (culture H5N1). [9][10][11] In this article, we report the synthesis and spectral characterization of 15 N-labeled azolo-1,2,4-triazines containing bridgehead nitrogen.…”