Synthesis of (R)‐ and (S)‐Ricinoleic Acid Amides and Evaluation of Their Antimicrobial Activity

Abstract

AbstractA series of fatty acid amides derived from (R)‐ and (S)‐ricinoleic acid and 4 cyclic and acyclic amines were synthesized in a proecological solvent‐free process with yields ranging from 43 to 88%. All S‐configured compounds and both enantiomers of amide with 2‐amino‐2‐methyl‐1‐propanol were obtained and studied in terms of biological activity for the first time. The evaluation of antimicrobial activity of (R)‐ and (S)‐ricinoleic acid derivatives against 13 different microorganisms representing Gram‐negative and Gram‐positive bacteria, yeast, and molds showed significant inhibitory activity against Gram‐positive bacteria, especially Micrococcus luteus and Bacillus subtilis, and against selected molds. Ethanolamine‐ and pyrrolidine‐derived amides showed the most promising antibacterial and antimold potential. Derivatives from ricinoleic acid and pyrrolidine were the most active against both selected molds, Aspergillus brasiliensis and Penicillium expansum. Moreover, the R‐configured analog was the most potent against B. subtilis. The amides of ricinoleic acid with ethanolamine exhibited significant potential to Staphylococcus aureus, which distinguished them from the rest of tested derivatives to which this bacterium was very resistant.