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