Synthesis and cytotoxicity of (-)-renieramycin G analogs

(−)-Renieramycin G and fifteen C-22 analogs were prepared employing l-tyrosine as the chiral starting material. These analogs, along with (−)-renieramycin G itself, were evaluated in vitro for cytotoxicity against HCT-8, BEL-7402, A2780, MCF-7, A549, BGC-823, Ketr3, KB, Hela cells. The IC₅₀ values of most of these analogs were at the level of μM. Among these analogs, 2-thiophenecarboxylate ester derivative 17 exhibited potent cytotoxic activity against KB cell line with the IC₅₀ of 20 nM. From this study, it could be concluded that the C-22 side chain played an important role in the cytotoxic potency and specificity of this class of (−)-renieramycin G derivatives.