Preparation of menisdaurigenin and related compounds

AbstractMenisdaurin (1), a cyano glucoside, was first isolated in 1978 fromMenispermum dauricum (Menispermaceae) and named after the plant. It has been also isolated from several plant sources. The stereochemistry of the aglycone part was first reported as (Z,4R,6S)-enantiomer of (4,6-dihydroxy-2-cyclohexen-1-ylidene)acetonitrile based on the CD spectrum of menisdaurilide (2), the α,β-unsaturated γ-lactone obtained by an acid hydrolysis of menisdaurin. Later, the absolute stereochemistry was revised as (Z,4S,6R) by X-ray crystal analysis of1 isolated fromSaniculiphyllum guangxiens. The aglycone part of menisdaurin (1) has not been obtained from1, because an acid hydrolysis of1 gave menisdaurilide (2), and enzymatic hydrolysis with emulsin did not give the aglycone. On the other hand, a compound named coculauril (3) was isolated fromCocculus lauriforius. This compound has the same planner structure corresponding to the aglycone of1, but the stereochemistry was reported to be (E,4R,6S). Here, we confirmed the absolute stereochemistry of1 by Mosher ’s method to be (Z,4S,6R), and prepared the aglycone of1, i.e., menisdaurigenin (4) by an enzymatic hydrolysis of1. We also revealed that4 is a different compound from3 and unstable in water and MeOH.
Source: Journal of Natural Medicines - Category: Drugs & Pharmacology Source Type: research