In Silico and In Vitro Studies of 1,3-Oxazol-4-yl Phosphonium Salts as Dual-Functional Antibacterial and Anticancer Agents

This report presents a comprehensive overview of the meticulous construction of a series of classification structure–activity relationship (SAR) models. These models are specifically designed to accurately predict the antibacterial activity of untested compounds against Acinetobacter baumannii. The binary models are based on 1687 chemicals and demonstrate a broad applicability domain for the structures for which they were designed. External validation with a test set confirms the models' capability to accurately predict the activity of newly designed compounds within the applicable range, achieving an accuracy of 78%–84%. The models were used to perform a virtual screening of a chemical library for compounds expected to be active against Acinetobacter baumannii. Six of the most promising compounds were synthesized and evaluated in vitro to assess their antibacterial activity. All tested molecules revealed high anti-A. baumannii activity. Our findings indicate that 3-oxazol-4-yl phosphonium salts demonstrate significant cytotoxicity. Notably, these compounds have been identified as potent anticancer agents, exhibiting IC₅₀ values ranging from 0.005 to 11.49 µM against the HEp-2 cell line.