SOLUTION CONFORMATION OF VIRGINIAMYCIN-S .2. CONFORMATION OF ALLOHYDROXYVIRGINIAMYCIN AND DEOXYVIRGINIAMYCIN-S

The experimental results of 1H- and 13C-NMR studies of allohydroxy-, and of deoxyvirginiamycin S strongly confirm the conformation that was proposed earlier for the parent virginiamycin S (Anteunis, Callens and Tavernier (1975) Eur. J. Biochem. 58, 259-268). The changing nature of a dipole-induced dipole interaction is responsible for the specific gradually increasing libration of the N-MePhe side chain along the series virginiamycin S, allohydroxy-, deoxyvirginiamycin S. Previous methods for the estimation of rotameric populations around the α, β bonds are critically evaluated and compared to the present results obtained from interpretation of geminal 2J(β) coupling constants. © 1979.