[Chemistry and antitumor activity of hainanensine analogues]

A synthetic analogue of hainanensine 2a was further modified in order to improve its antitumor activity. Six compounds 3-8, were obtained, and among these compounds 8 showed significant activity. The diastereomer (+/-)8B was resolved by (+) tartaric acid and (-)benzoyl-tartaric acid to the corresponding enantiomers (-)8B and (+)8B, respectively and their optical purities were determined by isotope dilution method as 93% and 96%. The antitumor activity of the newly obtained compounds were tested in vitro, and (-)8B was found to have an IC50 of 1.9 mol/L, eighteen times higher than the original compound 2a.