Antimicrobial activity of hydroxamic acids.

o-, m- and p-alkyloxybenzohydroxamic acids were synthesized and subjected to the examination for antibacterial and antifungal activity. All the hydroxamic acids tested were almost ineffective for pathogens examined of Enterobacteriaceae, but some of alkyloxybenzo- and fatty acyl-hydroxamic acid were found to be as highly effective for pathogenic fungi as butyl p-hydroxybenzoate being used as a comparison. The increase of carbon number of p-alkyloxybenzo- and fatty acyl-hydroxamic acid led to the increase in their antifungal activity, reached to the maximum at C6 in alkyloxy moiety and C10 in fatty acyl derivatives, and then the gradual decrease in both series. Considering the inhibitory power of hydroxamic acid on plant and bacterial urease, we discussed the possible correlation between antimicrobial activity and inhibitory powers on urease activity of the compounds.