B. Siva Kumar

Synthesis and bio-activity evaluation of tetraphenyl(phenylamino) methylene bisphosphonates as antioxidant agents and as potent inhibitors of osteoclasts in vitro.

A new series of tetraphenyl bisphosphonates have been elegantly synthesized by one-pot method and were characterized by elemental analysis, FTIR, 1H, 13C, 31P NMR, mass spectra and evaluated for their in vitro antibone resorptive activity by inhibiting growth of osteoclasts. Two bisphosphonates 3g and 3f showed marked inhibition ratio (8 μM and 10 μM) and emerged as lead compounds. All compounds were tested for their antioxidant (DPPH scavenging, reducing power and inhibition of lipid peroxidation). They exhibited potent in vitro antioxidant activity dose-dependently.

Synthesis and antimicrobial activity of bisphosphonates

Dimethyl [(substitutedphenyl)(6-oxo6λ5dibenzo[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, 1H, 13C, 31P NMR and mass spectral data found to possess higher antimicrobial activity then the standards.