- 8,9-Methylenedioxybenzo[i]phenanthridines: Topoisomerase I-targeting activity and cytotoxicity
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Substituted benzo[i]phenanthridines that have incorporated within their structure an 8,9-methylenedioxy group can exhibit topoisomerase I-targeting activity. Structure-activity studies were performed to examine the influence of saturation at the 11,12-positions of several substituted 8,9-methylenedioxybenzo[i]phenanthridines. The activities of these dihydro analogues were compared to those of their unsaturated analogues. In addition, the influence of varying substituents at the 2- and 3-positions within the A-ring of these 8,9-methylenedioxybenzo[i]phenanthridines on their relative potency as topoisomerase I-targeting agents and cell proliferation as determined using the MTT assay was investigated. 2,3-Dimethoxy-8,9-methylenedioxybenzo[i]phenanthridine and its 11,12-dihydro derivative were among the more potent analogues evaluated with regard to topoisomerase I-targeting activity and cytotoxicity.
- Li, Dajie,Zhao, Baoping,Sim, Sai-Peng,Li, Tsai-Kun,Liu, Angela,Liu, Leroy F.,LaVoie, Edmond J.
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p. 3795 - 3805
(2007/10/03)
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- A Formal Total Synthesis of the ACE Inhibitor K-13. An Application of Arene-Ruthenium Chemistry to Complex Chemical Synthesis
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Stoichiometric ruthenium activation of 4-chlorophenylalanine derivatives toward nucleophilic substitution, using phenoxide nucleophiles that are derived from protected dipeptides, allowed the formation of isodityrosine derivatives that are synthetic precursors to the ACE inhibitor K-13.An evaluation of carboxyl blocking groups revealed that a 2-bromoethyl ester is the most useful in terms of its compatibility with ruthenium complexation and subsequent nucleophile addition but that its removal is problematic.Conversion to iodoethyl ester using Finkelstein reaction conditions, in the presence of the peptide and amino acid functionality, provided a solution to this problem, since the iodoethyl group was easily removed on treatment with samarium diiodide.
- Pearson, Anthony J.,Lee, Kieseung
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p. 2304 - 2313
(2007/10/02)
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