Prenylated Benzene Metabolites from Melicope pteleifolia

Abstract

Chemical investigation on the stem and root of Melicope pteleifolia afforded three new prenylated benzene metabolites as racemic mixtures, named pteleifolins A–C (1–3, resp.). Their gross structures were elucidated on the basis of spectroscopic analysis, especially 2D‐NMR experiments. An enantiomer resolution of (±)‐1 using chiral HPLC was performed, and the absolute configuration of the enantiomers were determined to be (+)‐(S)‐1 and (−)‐(R)‐1 by means of circular‐dichroism analysis.

New Acetophenones and Chromenes from the Leaves of Melicope barbigera A. Gray

“…Differences were only found for the signals of the prenyl side chain and the aromatic carbon C-3′ ( δ 108.5), where the side chain is attached. Instead of one methyl group, one unsaturated methylene and one aliphatic hydroxyl group, we found the signals for two methyl groups at δ 1.59 (s, H-4″) and δ 1.68 (s, H-5″) together with one proton at δ 5.07 (t, H-2″) indicating the presence of a 3-methyl-but-2-en-1-yl side chain, found in many prenylated natural products such as O-prenylated acetophenones from M. obscura and M. obtusifolia or the prenylated benzene pteleifolins A isolated from M. pteleifolia [ 27 , 28 ]. The structure was additionally confirmed by the correlations found in the 2D-NMR spectra (see Figure 2 ).…”