Synthesis and antimicrobial activity of 3-arylamino-1-chloropropan-2-ols

A series of nine 3-arylamino-1-chloropropan-2-ols 2a-2i were synthesized and their anti-fungal activity against pathogenic strains of Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Candida albicans, and antibacterial activity against four pathogenic bacterial strains of Salmonella typhi, Pseudomonas aeruginosa, Streptococcus pneumonae and Staphylococcus aureus were evaluated using different assay systems. 1-Chloro-3-(4′-chlorophenylamino)-propan-2-ol was found to be the most active anti-fungal compound against three pathogenic strains under study, i.e., A. fumigatus, A. flavus and A. niger; the compound showed more than 90% inhibition of growth of A. fumigatus at a concentration of 5.85 microg/ml in disc diffusion assay. Interestingly, 1-chloro-3-(4′-chlorophenylamino)-propan-2-ol did not show any toxicity up to a concentration of 4000 microg/ml. Although 1-chloro-3-(4′-chlorophenylamino)-propan-2-ol was about 8 times less active than the standard compound amphotericin B, its toxicity was many more fold less than the toxicity of amphotericin B. Further, 1-chloro-3-(2′,6′-dichlorophenylamino)-propan-2-ol and 1-chloro-3-(3′,5′-dichlorophenylamino)-propan-2-ol were found to be the most active compounds against C. albicans. In the anti-microbial assay, 1-chloro-3-(2′,4′-dichlorophenylamino)-propan-2-ol and 1-chloro-3-(3′,5′-dichlorophenylamino)-propan-2-ol were found to be the most active compounds against Salmonella typhi and 1-chloro-3-(3′,4′-dichlorophenylamino)-propan-2-ol was found to be the most active compound against P. aeruginosa. Although, the activities of 1-chloro-3-(2′,4′-dichlorophenylamino)-propan-2-ol and 1-chloro-3-(3′,5′-dichlorophenylamino)-propan-2-ol are about half the activity of the standard anti-bacterial compound tetracycline, these compounds also were many fold less toxic than the standard drug.