Modular Synthesis of 1,2- and 1,1鈥?Disubstituted Ferrocenyl Carbohydrate Chloroquine and Mefloquine Conjugates as Potential Antimalarial Agents

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• 作者：Christoph Herrmann ; Paloma F. Salas ; Brian O. Patrick ; Carmen de Kock ; Peter J. Smith ; Michael J. Adam ; Chris Orvig
• 刊名：Organometallics
• 出版年：2012
• 出版时间：August 27, 2012
• 年：2012
• 卷：31
• 期：16
• 页码：5748-5759
• 全文大小：560K
• 年卷期：v.31,no.16(August 27, 2012)
• ISSN：1520-6041

文摘

The modular synthesis of novel organometallic antimalarials based on a 1,2- or 1,1鈥?disubstituted ferrocene scaffold (10 and 11) is presented. Ferrocenes were substituted via an ether linker with either 7-chloroquinoline or 2,8-bis(trifluoromethyl)quinoline, as a chloroquine or mefloquine derivative, respectively. Diisopropylidene-protected 6-amino-6-deoxyglucofuranose (18) or 6-amino-6-deoxygalactopyranose (21) was coupled via reductive amination to yield the target conjugates 24鈥?b>27 and 30. Yields could be substantially increased using a microwave reactor instead of conventional heating, which reduced the reaction time as well. After complete characterization these novel trifunctional conjugates were examined for their antiplasmodial activity in a chloroquine-susceptible (CQS) strain of Plasmodium falciparum (D10) and a chloroquine-resistant (CQR) strain (Dd2). The determined IC₅₀ values were in the low micromolar range. Introduction of the carbohydrate led to an increase in activity (>200 渭M (16, D10) to 1.2 渭M (24, D10)). The best activity was measured for 26 in Dd2 (IC₅₀ = 0.77 渭M). Resistance indices (RI) for all measured compounds were <1, indicating a higher activity in the chloroquine-resistant Dd2 strain in comparison to the chloroquine-susceptible D10 strain (RI = 0.93 for 24, RI = 0.15 for 25).