Efficient catalyst free green synthesis and in vitro antimicrobial, antioxidant and molecular docking studies of α-substituted aromatic/heteroaromatic aminomethylene bisphosphonates

A new series of α-substituted aromatic/heteroaromatic amino bisphosphonates have been synthesized by the three component condensation of diversely substituted amines with dialkyl phosphites and triethyl orthoformate without catalyst and solvent under microwave irradiation conditions. All the synthesized compounds were screened for their in vitro antibacterial, antifungal, antioxidant activity and molecular docking studies. The results revealed that among the synthesized compounds 3e, 3f, 3i and 3j showed high antibacterial, antifungal activity when compared to the standard drugs. Computational docking studies were made on the test compounds to predict how several amino bisphosphonates bind to DNA ligase. The bioactive compounds 3e and 3f have stronger inhibiting activity on human DNA ligase enzyme when compared with standard antibiotic ciprofloxacin. The compounds 3e, 3f, 3i and 3j showed better DPPH, NO and H2O2 scavenging activity.