*Article* **Synthesis of Oleanolic Acid-Dithiocarbamate Conjugates and Evaluation of Their Broad-Spectrum Antitumor Activities**

**Liyao Tang 1,†, Yan Zhang 1,†, Jinrun Xu 1,†, Qingfan Yang 2, Fukuan Du 1,3, Xu Wu 1,3, Mingxing Li 1,3, Jing Shen 1,3, Shuai Deng 1,3, Yueshui Zhao 1,3, Zhangang Xiao 2,3,\* and Yu Chen 1,3,\***


**Abstract:** Efficient and mild synthetic routes for bioactive natural product derivatives are of current interest for drug discovery. Herein, on the basis of the pharmacophore hybrid strategy, we report a two-step protocol to obtain a series of structurally novel oleanolic acid (OA)-dithiocarbamate conjugates in mild conditions with high yields. Moreover, biological evaluations indicated that representative compound **3e** exhibited the most potent and broad-spectrum antiproliferative effects against Panc1, A549, Hep3B, Huh-7, HT-29, and Hela cells with low cytotoxicity on normal cells. In terms of the IC50 values, these OA-dithiocarbamate conjugates were up to 30-fold more potent than the natural product OA. These compounds may be promising hit compounds for the development of novel anti-cancer drugs.

**Keywords:** structural modification; oleanolic acid; natural product derivative; dithiocarbamate; hybrid strategy; antitumor activity
