New Antifungal Chromenyl Ketones and their Pentacyclic Dimers from Hypericum revolutum VAHL

Two new 2H-1-benzopyranyl ketones 1 and 2 and three new pyrano3,2-c: 4,5,6-d′ e′]di1]benzopyrandiyl diketones 3 , 4a / 4b , and 5 have been isolated from the leaves and twigs of Hypericum revolutum VAHL (Guttiferae). The structure of 3 (hyperevoline) was established by X-ray analysis as 1,1′-1,13,13a,13b-tetrahydro-5,8,10-trihydroxy-2,2,6,9,13,13-hexamethyl-2H, 7aH-pyrano3,2-c:4,5,6-d′e′]di1]benzopyran-4, 11-diyl]bis2-methyl-1-propanone]. The structures of the isolated compounds were established by spectroscopic (UV, IR, EI-MS, ¹H- and ¹³C-NMR) and chemical (acetylation and acidic dimerization) methods.