Abstract
Configurational and conformational analysis of unique phloroglucinol-sesquiterpene coupled compounds, macrocarpals H, I, and J (1-3), showing potent antibacterial activity and inhibitory effect of glucosyltransferase, was made by nuclear Overhauser enhancement (NOE) experiments and computational chemical methods. The configuration at C-9' of the side chains of 1-3 was elucidated as 1 : S, 2 : R, and 3 : S, by the structures obtained by the Monte Carlo (MC) calculation using MM2* force field implemented in MacroModel/Batchmin, followed by semiempirical molecular orbital calculations, whose stable conformation of macrocarpals H, I, and J was well satisfied by the NOEs observed around H-9'.
