Synthesis and Preliminary Anticancer Evaluation of 4‐<i>C</i> Derivatives of Diphyllin

The natural lignan diphyllin has shown promising antitumor activity, although its clinical advancement has been impeded by challenges such as low solubility, poor metabolic stability, and limited potency. In response, we developed and synthesized two sets of diphyllin 4-C derivatives, comprising six ester derivatives and eight 1, 2, 3-triazole derivatives. Notably, among these derivatives, 1, 2, 3-triazole derivatives 7c and 7e demonstrated the most potent cytotoxic effects, with IC₅₀ values ranging from 0.003 to 0.01 μM. Treatment with 0.2 μM of 7c and 7e resulted in a reduction of V-ATPase activity in HGC-27 cells to 23% and 29%, respectively.