Synthesis and antitumor activity of 20(S)-camptothecin derivatives: A-ring modified and 7,10-disubstituted camptothecins. |
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Authors: | S Sawada S Matsuoka K Nokata H Nagata T Furuta T Yokokura T Miyasaka |
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Institution: | Yakult Central Institute for Microbiological Research, Tokyo, Japan. |
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Abstract: | 20(S)-Camptothecin derivatives having nitro, amino, chloro, bromo, hydroxyl and methoxyl groups in the A-ring were synthesized. B-Ring hydrogenated camptothecin (2a) was converted into 10-hydroxycamptothecin (6e) by treatment with lead tetraacetate in trifluoroacetic acid. 10-Substituted derivatives (6) were obtained by a photoreaction of N-oxides (9). The cytotoxicity of the A-ring modified camptothecins was evaluated against KB cells in vitro and leukemia L1210 in mice. 7-Ethyl-10-hydroxycamptothecin (6i) was identified as a potential derivative for further modification. |
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