Synthesis of Leonosides E and F derived from Leonurus japonicas Houtt

Synthesis of phenylethanoid glycosides from acrylic esters of glucose and aryldiazonium salts via palladium-catalyzed cross-coupling reactions and evaluation of their anti-Alzheimer activity

Cinnamic acid-containing sugar compounds such as phenylethanoid glycosides are widely present in nature and display various biological activities. In this work, the synthesis of trans-cinnamic acid containing phenylethanoid glycosides was achieved via palladium-catalyzed cross-coupling reactions between glycosyl acrylic esters and aryldiazonium salts. A wide range of functionalized aryldiazonium salts were successfully coupled with 6-O- and 4-O-acrylic esters of glucose under optimized conditions. The reactions proceeded at room temperature in the absence of additives and base. The desired products were obtained in good to excellent yields. Selected compounds from the library were screened for anti-Alzheimer activity, while compound 16 displayed significant inhibitory activities against butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) enzymes.

An Approach to the Synthesis of Electron-Rich and Hindered Esters and Its Application to the Synthesis of Acteoside

Electron-rich esters are ubiquitously distributed in natural products and play a central role in bioactivities. Herein, we disclose an efficient, mild, and general esterification approach to the synthesis of these esters by employing gold(I)-catalyzed acylation reaction with alkyne-tethered mixed anhydrides and alcohols. This method can be applied to ester-bond formation in complex substrates and facilitates efficient synthesis of acteoside, which belongs to the family of phenylethanoid glycosides and possesses a broad range of bioactivities.

Synthesis of Carbohydrate-based Natural Products from Leonurus japonicus and their Biological Evaluation as Anti-oxidants

Natural products are important materials that have found a wide variety of uses, especially in medicine. Traditional Chinese medicine (TCM) has especially taken advantage of natural products and compounds found in Leonurus, a species of herb used extensively in TCM to treat various ailments. Herein we describe the synthesis of three natural products from Leonurus japonicus and our investigation of their hepatoprotective properties.