CONFIGURATIONAL AND CONFORMATIONAL-ANALYSIS OF MARCOCARPAL-H, MARCOCARPAL-I, AND MARCOCARPAL-J FROM EUCALYPTUS-GLOBULUS

Configurational and conformational anal!;sis of unique phloroglucinol- sesquiterpene coupled compounds, macrocarpals H, I, and J (1-3), showi ng potent antibacterial activity and inhibitory effect of glucosyltran sferase, was made by nuclear Overhauser enhancement (NOE) experiments and computational chemical methods. The configuration at C-9' of the s ide chains of 1-3 was elucidated as 1: S, 2: R, and 3: S, by the struc tures obtained by the Monte Carlo (MC) calculation using MM2 force fi eld implemented in MacroModel/Batchmin, followed by semiempirical mole cular orbital calculations, whose stable conformation of macrocarpals H, I, and 3 Has well satisfied by the NOEs observed around H-9'.