New acylphloroglucinols from a crude acetone extract of Dehnh. leaf.

Acylphloroglucinols are well-known secondary metabolites which exhibit a variety of structures and bioactivities. The investigation of a crude acetone extract of leaves led to the isolation of two new acylphloroglucinols, eucalypcamals O and P ( and ) together with seven phloroglucinols (-), and a benzene derivative (). Their chemical structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and mass spectroscopy. The absolute configurations of compounds and were established by comparison of experimental and calculated electronic circular dichroism (ECD) data. In the putative biosynthetic pathway, eucalypcamals O and P should be derived from hetero-Diels-Alder reaction between grandinol and -isoeugenol.