Synthesis and biological activity of 2-hydroxynicotinoyl-serine-butyl esters related to antibiotic UK-3A

Three novel 2-hydroxynicotinoyl-serine-butyl esters, AD-1, AD-2 and AD-3 have been synthesized and subsequently evaluated on the basis of their toxicity levels and antibiotic activities. AD-3 demonstrated significant activity as a growth inhibitor of Bacillus subtilis and Staphylococcus aureus. Novel 2-hydroxynicotinoyl-serine-butyl esters have been synthesized. Three-step reactions from l-serine by esterification with n-butanol, amidation with 2-hydroxynicotinic acid and esterification with the corresponding carboxylic acids gave AD-1, AD-2 and AD-3. The toxicity level of esters were determined by Brine shrimp assay, and antibiotic activity was tested against Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Candida albicans. AD-3 showed greater activity as a growth inhibitor of B. subtilis and S. aureus compared to Antimycin A3.