Synthesis and In-Vitro Antitumor Activities of Some Mannich Bases of 9-Alkyl-1,2,3,4-tetrahydrocarbazole-1-ones

A novel series of 2‐substituted aminomethyl‐9‐alkyl‐1,2,3,4‐tetrahydrocarbazole‐1‐ones 5a–q was synthesized via aminomethylation of 9‐alkyl‐1,2,3,4‐tetrahydrocarbazole‐1‐ones 4a–e with hydrochlorides of the respective amines 6a–m. The structures of these newly synthesized compounds were characterized by 1H‐NMR, MS, and elemental analysis. All the compounds were tested for their cytotoxic activity in vitro against four human tumor cell lines including human non‐small lung cancer cells (A549), human gastric adenocarcinoma (SGC), human colon cancer cell (HCT116), human myeoloid leukemia cells (K562), and one multi‐drug resistant subline (KB‐VCR). Most compounds showed moderate to potent cytotoxic activity against the tested cell lines. Preliminary mechanism research indicated that the most promising compound, 2‐diethylaminomethyl‐9‐methyl‐1,2,3,4‐tetrahydrocarbazole‐1‐one 5c, exhibited a potential inhibitory effect against microtubule.