Abstract
The configuration of two isomeric antibiotics, Naramycin-A (cycloheximide) and Naramycin-B was elucidated as follows, the plane structure being depicted as (I) : 1) Asymmetric carbon at α-position in both antibiotics has the same configuration. 2) Absolute configuration of asymmetric carbons at 4-position is the same in both antibiotics and belongs to (S)-series. 3) Both antibiotics have an equatorially oriented 6-[α-hydroxy-β-(2, 6-dioxo-4-piperidinyl) ethyl] group, but the configuration of asymmetric carbon at 6-position is different in the two antibiotics. 4) Assuming that the partial rotation due to α-carbon in both antibiotics is the same, because their absolute configuration is the same, Naramycin-A has (4S : 6S)-structure and Naramycin-B has (4S : 6R)-structure.
