Synthesis and biological evaluation of some novel N,N′-bis-(1,2,4-Triazin-4-yl)-dicarboxylic acid amides and some fused rings with 1,2,4-triazine ring

Abstract

Some of novel N,N′-bis-(1,2,4-triazin-4-yl)dicarboxylic acid amides (2-5) and thiadiazolo[2,3-b][1,2,4]triazin-7-yl carboxylic acid derivatives (6,7) were prepared by heating 4-amino-6-methyl-5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-triazine (1) with different dicarboxylic acids (oxalic, malonic, fumaric, maleic, succinic, and phthalic acids respectively) in POCl3. Refluxing 1 with 1-chloro-2,4-dinitrobenzene in DMF yielded 3-methyl-6-nitro-10H-benzo[1,2,4]thiadiazino[2,3-c] [1,2,4]triazin-4-one (8). Condensation of 1 with 2,4-pentandione in refluxing acetic acid furnished 6-methyl-4-(1-methyl-3-oxobut-1-enylamino)-3-thioxo-3,4-dihydro-2H-[1,2,4] triazin-5-one (9). 3,8-Dimethyl[1,2,4] triazino[3,4-b][1,3,4]thiadiazine-4,7-dione (11) was prepared by refluxing 1 with 2-bromopropionyl bromide in anhydrous benzene to afford the corresponding N-acetylated derivative 10, which was cyclized by using triethylamine. Also, some triazinylquina-zolinones 13a,b were obtained by fusion of 1 with 6-bromo(and/or 6,8-dibromo)-2-methyl-3,1-benzoxazin-4H-ones.