Synthesis and Antimicrobial Evaluation of Newly Synthesized N,S‐Bisphosphonate Derivatives

An easy strategy for the synthesis of tetraethyl-2-(3-mercapto-4H-1,2,4-triazol-4-ylamino)-2-(aryl)ethane-1,1-diyldiphosphonate and tetraethyl-(6-(aryl)-5,6-dihydro[1,2,4]triazolo[3,4-b]-[1,3,4]thiadiazol-6-yl)methylenediphosphonate derivatives with reasonable 67–85% overall yields has been developed. The approach was achieved via applying Wadsworth–Horner–Emmons reagent, tetraethylmethylenebisphosphonate, to 4-(arylideneamino)-4H-1,2,4-triazole-3-thiols under phase-transfer catalysis conditions. Screening results of antimicrobial potency for 12 out of 17 methylene-1,1-bisphosphonate products were reported. Two of the tested thiadiazolomethylenebisphosphonates displayed better spectrum of antimicrobial activity against the pathogens, compared with that of the positive controls.