Bu-2313, A NEW ANTIBIOTIC COMPLEX ACTIVE AGAINST ANAEROBES

III. SEMI-SYNTHESIS OF Bu-2313 A AND B, AND THEIR ANALOGS

Abstract

Analogs of Bu-2313 A and B were prepared by C-acylation of tetramic acid derivatives with the dienoic acid moiety obtained by periodate oxidation of Bu-2313 A or B. The C-acylation proceeded in the presence of a strong base such as potassium t-butoxide, sodium hydride or lithium hydride, whereas the use of triethylamine afforded O-acylated products. The semi-synthetic Bu-2313 analogs exhibited antibacterial spectra similar to the parent antibiotic but none exceeded Bu-2313 B in activity.