Three new phloroglucinol derivatives from Hypericum scabrum

A chemical investigation on the aerial parts of Hypericum scabrum L. resulted in the isolation of three new phloroglucinol derivatives, hyperscabrins A (1), B (2), and C (3), together with one known compound, (2R,3R,4S,6R)-3-methyl-4,6-di(3-methyl-2-butenyl)-2-(2-methyl-1-oxopropyl)-3-(4-methyl-3-pentenyl)-cyclohexanone (4). The structures were elucidated by means of spectroscopic methods, including MS, IR, 1D NMR, and 2D NMR, and the absolute configurations of chiral centers in these phloroglucinol derivatives were determined for the first time by studying their circular dichroism spectra.