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

“…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.…”

“…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].…”

1,2,4-Triazine Chemistry Part II: Synthetic approaches for phosphorus containing 1,2,4-triazine derivatives

“…Also, novel seven-membered phosphorus heterocycles was achieved by reaction of 4-amino-3-mercapto-6-methyl-1,2,4triazin-5(4H)-one (47) with phenacyl triphenylphosphonium bromide in boiling dimethylformamide containing a catalytic amount of piperidine to afford 1,2,4-triazino[4,3-f] [1,5,6,2] thiadiazaphosphepine 76 derivative (Scheme 25) [28]. Formation of compound 76 may occur through the attack of the electron pairs of the SH group on phosphorus atom of the phosphonium salt to remove hydrogen halide which may afford the intermediates 75, followed by an intramolecular nucleophilic attack of the amino group on carbonyl group with elimination of water to 76 [28].…”

“…Various substituted 1,2,4-triazine derivatives have a great importance as biological agents in medicinal and agricultural fields [1][2][3][4][5][6]. Recently, this class of compounds have gained considerable interest because of their herbicidal [7,8], antimicrobial [9][10][11], anti-HIV [12] and anticancer activities [13,14].…”

Synthesis of some new bipyridines, thieno[2,3‐b]pyridines, and pyrazolo[3,4‐b]pyridines

“…In the last decades, they are used as anticancer drugs, antihypertension, antifungal reagents, pesticides, herbicides, and plant growth reagents [4][5][6][7]. Similarly, thienopyridine derivatives are characterized by a very broad area of biological activities, such as antiallergic [8], antiatherosclerotic [9], antibacterial [10][11][12], anticancer [13], antiviral [14,15], antihypertensive [16,17], antidepressant [18], antihistaminic [19], antimicrobial, and neurotropic activities [20][21][22][23]. Recently, it has been reported that many pyridine derivatives showed strong cytotoxicity against several human cancer cell lines [24][25][26].…”