A series of combretastatin A-4 (CA-4) analogues were synthesized, and their cytotoxic effects against murine Colon 26 adenocarcinoma and inhibitory activity on tubulin polymerization were evaluated. Since CA-4 has limited aqueous solubility, the target compounds were designed to improve solubility by introduction of a nitrogen-containing group. Among the compounds synthesized, those with an amino moiety in place of the phenolic OH of CA-4 showed potent antitubulin activity and cytotoxicity against murine Colon 26 adenocarcinoma in vitro. Some of the compounds which were potent in vitro were evaluated in the murine tumor model Colon 26 in vivo. Among these, 13bHCl, 21aHCl, and 21bHCl showed significant antitumor activity in the animal model, while CA-4 was ineffective. 13bHCl and 21aHCl were further evaluated in two murine tumor models (Colon 38 and 3LL) and human xenografts HCT-15. These compounds showed potent antitumor activity comparable or superior to that of CDDP. The structure-activity relationships of this series of compounds are also discussed.

No abstract

Interfacial charge transfer is one of the most important fundamental steps in the charge and discharge processes of intercalation compounds for rechargeable batteries. In this study, temperature-dependent electrochemical impedance spectroscopy was carried out to clarify the origin of the high power output of aqueous batteries with Prussian blue analog electrodes. The activation energy for the interfacial charge transfer, E a , was estimated from the temperature dependence of the interfacial charge transfer resistance. The E a values with Li + and Na + aqueous electrolytes were considerably smaller than those with organic electrolytes. The small E a values with aqueous electrolytes could result from the fact that the Coulombic repulsion at the interface is largely suppressed by the screening effect of hydration.

Mg 2+ intercalation/deintercalation is achieved by using aqueous electrolytes and Prussian blue analog electrodes. Ex situ X-ray diffraction evidenced the solid solution process of Mg 2+ intercalation/deintercalation, while the 57 Fe Mössbauer spectroscopy and Xray absorption near edge structure revealed redox of both Cu and Fe.