Activated carbon/Brønsted acid-promoted aerobic benzylic oxidation under “on-water” condition: Green and efficient synthesis of 3-benzoylquinoxalinones as potent tubulin inhibitors

Green chemistry is becoming the favored approach to preparing drug molecules in pharmaceutical industry. Herein, we developed a clean and efficient method to synthesize 3-benzoylquinoxalines via activated carbon promoted aerobic benzylic oxidation under “on-water” condition. Moreover, biological studies with this class of compounds reveal an antiproliferative profile. Further structure modifications are performed and the investigations exhibited that the most active 12a could inhibit the microtubule polymerization by binding to tubulin and thus induce multipolar mitosis, G2/M phase arrest, and apoptosis of cancer cells. In addition, molecular docking studies allow the rationalization of the pharmacodynamic properties observed. Our systematic studies provide not only guidance for applications of O2/AC/H2O system, but also a new scaffold targeting tubulin for antitumor agent discovery. [Display omitted] •A clean and green method to synthesize 3-benzoylquinoxalines under “on-water” condition was developed.•As anticipated, compound 9d exerted potent antitumor efficacy.•Further structural optimization led to a promising compound 12a, which is a novel tubulin inhibitor.•This work provides a green version for medicinal chemists to assemble molecules in the seeking stage of drug discovery.