Determination of the Relative Configurations in the Side Chains of the Antibiotics Hedamycin and Pluramycin A; Synthesis and NMR. Data of Suitable Model Compounds

Several diepoxyhexanoates and epoxyhexenoates were prepared by epoxidation of methyl 2‐methyl‐2,4‐hexadienoate or by Darzens condensation. Their 1 H‐ and 13C‐NMR. spectra were measured and assigned. Comparison of these data with the spectra of the antibiotics hedamycin (1) and pluramycin A (2) allowed the determi‐nation of the relative configurations in the side chains of these antibiotics. They were found to be (14R*,16S*,17R*,18S*) for hedamycin (1) and (14R*,16S*,17Z) for pluramycin A (2).