Studies on the Agalwood (Jinko). VII. : Structures of Phenylethyl-chromone Derivatives AH₇, AH₈ and AH₉

Abstract

Three new phenylethylchromone derivatives, tentatively named AH₇, AH₈ and AH₉, were isolated from acetone and pyridine extracts of agalwood (jinko) from Kalimantan. AH₇ from the pyridine extract was characterized as 5, 8-dihydroxy-2-(2-phenylethyl)chromone, and AH₈ from the acetone extract was elucidated to be 6, 7-dimethoxy-2-[2-(4-methoxyphenyl)chromone. AH₉, acetylated in order to separate it from the mixture, was concluded to be (5S, 6S, 7R)-5a', 6a, 7a-triacetoxy-2-[2-(2-acetoxyphenyl)ethyl]-5, 6, 7, 8, 8-pentahydrochromone on the basis of the proton nuclear magnetic resonance (¹H-NMR) spectrum, dihedral angle and circular dichroism (CD) spectral data.