Polyoxin analogs. III. Synthesis and biological activity of aminoacyl derivatives of polyoxins C and L.

Publisher Website
Google Scholar
Abstract
A number of aminoacyl derivatives of nucleoside antibiotics, polyoxins C and L were prepared. Aminoacylation was performed in aqueous dimethylformamide with an equimolar N-carbobenzoxyamino acid p-nitrophenyl ester in the presence of an equimolar triethylamine or N-methylmorphine. Catalytic hydrogenolysis of the condensation product followed by chromatographic purification afforded the aimed compounds in moderate yields. Antifungal activities were tested with several lines of phytopathogenic fungi, which led to some conclusion upon structure-activity relationship regarding the N terminal amino acid: the .alpha.-L-amino group is essential for the activity and the alkyl chain length and especially nature of the .omega.-substituents affect considerably the activity. Many of the aminoacyl derivatives of polyoxin L retained moderate activity. None of the compounds prepared showed broader antimicrobial spectrum than the natural polyoxins.