Synthesis and structure elucidation of five new conjugates of oleanolic acid derivatives and chalcones using 1D and 2D NMR spectroscopy

Five new conjugates of oleanolic acid derivatives and chalcones have been designed and synthesized. The structure elucidation of these conjugates was accomplished by using extensive 1D ( 1 H, 13 C) and 2D NMR spectroscopic studies (COSY, HSQC and HMBC); and α ‐glucosidase inhibitory activity is reported for these conjugates. Compound 2b (IC 50 = 47.5 µ m ) displayed much stronger activity than oleanolic acid and acarbose. Copyright © 2012 John Wiley & Sons, Ltd.