Microwave synthesis and antimicrobial evaluation of selected aminophosphonates

In the search for new bioactive molecules, a series of new molecules from the phosphonate family were synthesized via the Kabachnik-Fields reaction (phosphonate ester) and the Irani-Moedritzer reaction (phosphonic acids). Their structures were characterized by various spectroscopic methods, including IR and UV-vis. The synthesized compounds were screened for in vitro antimicrobial activity against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria using the well method. The results also showed that all the products synthesized exhibited good activity with a zone of inhibition; D>8, except one product against S. aureus bacteria.
The three products were tested for their antifungal effects against three pathogenic fungal strains, namely Candida albicans, Aspergillus niger and Penicillium notatum. The results show that the zones of maximum inhibition were observed against P. notatum (35.5mm). So the biological tests showed that all the compounds studied exhibited high antibacterial and antifungal activities.
The aim of the present work is therefore to synthesize aminophosphonate derivatives using microwaves. Microwaves open up new opportunities for synthetic chemists in the form of new reactions that are difficult to use with conventional heating. Interest in microwave-assisted organic synthesis (SOAM) has been growing in recent years. The short reaction times provided by microwave synthesis make it ideal for rapid reaction screening and optimization of reaction conditions.