Glycoric Acid, a New Degraded Carotenoid from Glycosmis arborea

The title compound, (7E)-3β,6β-dihydroxy-10-normegastigm-7-en-9-oic acid, (1) [(E)-3-(1,4-dihydroxy-2,2,6-trimethyl-1-cyclohexyl)acrylic acid, C₁₂H₂₀O₄], which is a kind of degraded carotenoid, was isolated from the hepatoprotective n-butanol soluble fraction of the methanol extract of Glycosmis arborea. From NMR and other spectral analyses, (1) was inferred to possess a new 10-normegastigmane skeleton and its molecular formula was determined by high-resolution mass spectrometry. We describe herein the conformation of the ring system and configuration of the substituents based on X-ray diffraction analysis. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

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