Antimicrobial Evaluation and Structure Activity Relationship (SAR) of 1,ω-bis[4-[(arylideneamino/ alkylideneamino/ or arylalkylideneamino)carbamoyl]phenoxy]alkanes

Abstract

Different 1,ω-bis[(4-[(arylideneamino/alkylideneamino/ or arylalkylideneamino)carbamoyl]phenoxy]a- lkanes 1-20, 25 were synthesized and their inhibitory effects against different strains of Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli), yeast (Candida albicans) and fungi (Aspergillus fumigatus, Penicillium italicum and Syncephalastrum racemosum) were evaluated using the diffusion agar technique. The screening results showed that most of the tested compounds exhibited wide spectrum activity against the test organisms and many of them revealed higher inhibitory effects against some organisms, when compared to standard antibacterial Chloramphenicol and antifungal Terbinafin. The structure activity relationship study was achieved via studying the effect of the aliphatic spacer length between the two ethereal oxygen atoms and the effect of functional groups attached to the terminal ends of the titled compounds. Thus, amomg compounds 1-10 that have short spacer between the phenoxy groups, at all concentrations, compound 5 with the dimethylaminophenyl group and compound 6 with the 2-hydroxyphenyl group exhibited the highest inhibitory effect. Among compounds 11-20 having medium spacer between the phenoxy groups, compound 12 having p-tolyl group, at all concentrations, exhibited the highest inhibitory effect. Among compounds 21-25 with long spacer between the phenoxy groups, compounds 21, with the phenyl group and compound 22 with the 4-methoxyphenyl group, at all concentrations, exhibited the highest inhibitory effect.