Synthesis and Antimicrobial Activity of Bisphosphonates

Dimethyl [(substitutedphenyl)(6-oxo6λ 5 dibenzo[ d,f][1,3,2]dioxaphophepin-6-yl)methyl]phosphonates (5a-j) were synthesised through a three step process involving preparation of dimethyl hydroxy(substitutedphenyl)methyl-phosphonates (4a-j) and their reaction with 6-bromodibenzo[ d,f][1,3,2]dioxaphosphepine (2) in dry toluene in the presence of triethylamine at 50–60°C. Tetramethylguanidine (TMG) as a catalyst was found to increase the yields and purity of the products. These compounds were characterised by IR, 1 H, 13 C, 31 P NMR and mass spectral data found to possess higher antimicrobial activity then the standards.