Synthesis and biological activities of [N-MeLeu5] didemnin B

Based on information from X-ray, NMR, and SAR data, the N,O-diMeTyr5 unit of didemnim B was believed to interact with receptors. To ascertain the importance of this unit, an analog was synthesized in which the N,O-diMeTyr5 moiety was replaced with N-McLeu. Preliminary biological testing showed that the analog retained antitumor activity and the ability to inhibit protein biosynthesis.