Search

Chemical investigation of Lansium domesticum has led to the isolation of two undescribed compounds, namely 17(20)E-dyscusin B (1) and 17(20)Z-dyscusin B (2), as well as three known ones (3 – 5). Structural elucidation was accomplished by the analysis of NMR, MS and IR data. Compounds 1 and 2 were a pair of Δ17(20) geometric isomers of pregnane steroids and showed the significant nitric oxide (NO) inhibitory activities.

The practical synthesis of important natural polyphenolic stilbenes, including resveratrol, piceatannol and oxyresveratrol, through Perkin methodology is described. Starting from 3,5-dihydoxyacetophenone (1), the common intermediate 3,5-dimethoxyphenylacetic acid (3) can be obtained via methylation and Willgerodt-Kindler reaction. Perkin condensations between (3) and substituted phenylaldehydes 4 furnished E-2,3-diarylacrylic acids 5, followed by decarboxylation in Cu/quinoline giving stilbene intermediates 6 which bear the Z-configuration. Finally, through a simultaneous demethylation/isomerization process in AlI₃/CH₃CN system, the target compounds 7a-c can be obtained respectively in good to high overall yields. The synthetic method proved to be more concise, trans-specific, mild, economical and commonly applicable.