Cyclohexanecarboxylic‐Acid Derivatives from Psiadia trinervia

From a MeOH extra of Psiadia trinervia, seven phenolic compounds were isolated by gel filtration and reversed‐phase chromatography. Six of them are known compounds, namely 3,4‐di‐O‐caffeoylquinic acid (2), 3,5‐di‐O‐caffeoylquinic acid (3), caffeic acid, and three 3‐methoxyflavonoids. Compound 1 is a 3,4‐di‐O‐caffeoyl derviative of (1S,3R,4R,5R)‐1,3,4, 5‐tetrahydroxycyclohexanecarboxylic acid, a novel steroisomer of (−)‐quinic acid. Following hydrolytic treatment of the MeOH extract, ethyl 3‐O‐caffeoylquinate (4), ethyl 3,4‐di‐O‐caffeoylquinate (5), and ethyl 3,5‐O‐caffeoylquinate (6) were isolated. The latter three compounds are artifacts. The configuration of 1‐3 was established by NMR and CD (exciton chirality method).