A radical substitution reaction of 20(S)-camptothecin (1) with methanol furnished 7-hydroxymethylcamptothecin (2). Reaction of 1 with primary alcohols higher than methanol gave 7-alkylcamptothecins (4), of which alkyl groups were one carbon less than the alcohols used and also 7-hydroxyalkylcamptothecins (5). For the preparation of 7-alkylcamptothecin (4), aldehydes were used as a radical source and several alkylated derivatives were synthesized. 7-Acyloxymethyl derivatives (6), 7-carbaldehyde (7), iminomethyl derivatives (10), acid (11), esters (12) and amides (13) were synthesized starting from 2. 7-Ethyl- (4b) and 7-propylcamptothecin (4c), acyloxymethyl compounds 6a, 6c and ethyl ester (12b) exhibited higher antitumor activity than 1 against L1210 in mice. © 1991, The Pharmaceutical Society of Japan. All rights reserved.
CITATION STYLE
Sawada, S., Nokata, K. I., Furuta, T., Yokokura, T., & Miyasaka, T. (1991). Chemical Modification of an Antitumor Alkaloid Camptothecin: Synthesis and Antitumor Activity of 7-C-Substituted Camptothecins. Chemical and Pharmaceutical Bulletin, 39(10), 2574–2580. https://doi.org/10.1248/cpb.39.2574
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