20(S)-20-O-Camptothecin β-Aminopropionate: Novel Synthesis and Antitumor Activity in vitro1

To improve the biological anticancer activity of 20(S)-camptothecin, a novel class of 20(S)-20-O-camptothecin β-aminopropionates were designed and synthesized with camptothecins as the starting materials, through acylation with acryloyl chloride followed by Michael's addition. Twelve esters, 1a-1d, 4a-4d and 5a-5d, were synthesized and evaluated by using MTT assay method. The results demonstrate that all these compounds show a potential cytotoxicity on KB, HT-29, HCT-8 and Bel7402 tumor cell lines. Some compounds, 1d, 4c, 5b, 5c and 5d, show a higher cytotoxicity on KB and HCT-8 compared with camptothecin.