Synthesis of some new biologically active thiadiazolotriazinones

Synthesis and antibacterial activity of some new thiadiaza/triazaphospholes, thiadiaza/triaza/tetrazaphosphinines and thiadiaza/tetrazaphosphepines containing 1,2,4-triazinone moiety

“…6-Methyl-2-oxido-2-phenyl-1,2-dihydro-7H- [1,3,4,2]thiadiazaphospholo [5,4-c] [1,2,4]triazin-5-one (2) was synthesized by the reaction of 4-amino-3-mercapto-6-methyl-1,2,4-triazin-5(4H)-one (1) with phenylphosphonic dichloride in THF containing 2 equiv amounts of triethylamine to remove hydrogen chloride (Scheme 1). The molecular structure of 2 was deduced from its IR spectrum, which showed the absorption bands of NH, C]O and P]O groups at 3158, 1681 and 1225 cm À1 , respectively.…”

“…Reaction of compound 1 with acetyl triphenylphosphonium chloride and phenacyl triphenylphosphonium bromide in boiling DMF containing a catalytic amount of piperidine afforded 1,2,4-triazino [4,3-e] [1,4,5,2]thiadiazaphosphinine 4 and 1,2,4-triazino [4,3-f] [1,5,6,2]thiadiazaphosphepine 6 derivatives, respectively (Scheme 1). Formation of compounds 4 and 6 may occur through the attack of electrons of the lone pair of the SH group on phosphorus atom of the phosphonium salt to remove hydrogen halide which may afford the intermediates 3 and 5, respectively, followed by an intramolecular nucleophilic attack of the amino group on carbonyl group with elimination of water to give 4 and 6, respectively.…”

“…Consequently, compound 7 was heated under reflux with diphenylphosphoryl acetonitrile for 12 h in THF in the presence of sodium hydride as a catalyst to afford 7-(4-chlorophenyl)-8- [1,2,4]triazine-8-carbonitrile (13) and not 1,3,4-thiadiazaphosphepine derivative 11 (Scheme 2). This reaction pathway proceeds via C-nucleophilic attack by the reactive methylene of diphenylphosphoryl acetonitrile on the N-N]CH-Ar moiety to give the intermediate 10 which underwent cyclization by elimination of one molecule of H 2 S followed by an air oxidation process (route b).…”

“…Various substituted 1,2,4-triazin-5-one derivatives have a great importance as biological agents in medicinal and agricultural fields [1][2][3][4][5]. Recently, significant activities have been directed toward this class of compounds, in particular, 4-amino-1,2,4-triazin-5(2H)-one derivatives which have considerable interest because of their herbicidal [6,7], antimicrobial [8][9][10], anti-HIV [11] and anticancer activities [12,13].…”

Synthesis and Biological Activities Evaluation of Some New 1,2,4-Triazinone Derivatives Bearing Sulfonamide Moiety

“…Among them, 1,2,4-triazine derivatives are known to exhibit various pharmacological [24] and medicinal applications [25][26][27]. Taking into account all previous commentaries of the biological activities of sulfonamides and in continuation of our study on the synthesis of biologically active heterocycles [28,29], efforts have been made to synthesize a series of new 1,2,4-triazinone derivatives incorporating sulfonamide moiety via cyclocondensation reaction of nitrilimines bearing moiety of sulfonamide with α-aminoesters in anticipation of expected interesting biological activities.…”