Synthesis of Polycyclic Ether-Benzopyrans and In Vitro Inhibitory Activity against Leishmania tarentolae

Abstract

Construction of a focused library of polycyclic ether-benzopyrans was undertaken in order to discover new therapeutic compounds that affect Leishmania growth and infectivity. This is especially of interest since there are few drug therapies for leishmaniasis that do not have serious drawbacks such high cost, side effects, and emerging drug resistance. The construction of these polycyclic ether-benzopyrans utilized an acetoxypyranone-alkene [5+2] cycloaddition and the Suzuki-Miyaura cross-coupling. The multi-gram quantity of the requisite aryl bromide was obtained followed by effective Pd-catalyzed coupling with boronic acid derivatives. Compounds were tested in vitro using the parasitic protozoan, Leishmania tarentolae. Effects of concentration, time, and exposure to light were evaluated. In addition, the effects on secreted acid phosphatase activity and nitric oxide production were investigated, since both have been implicated in parasite infectivity. The data presented herein are indicative of disruption of the Leishmania tarentolae and thus provide impetus for the development and testing of a more extensive library.

Activity of Platinum-Based Cathode Electrocatalysts in Oxygen Redaction for Proton-Exchange Membrane Fuel Cells: Influence of the Ionomer Content

“…During measurements without any ionomer, the Pt-based catalysts exhibit excellent activity in the ORR in a three-electrode cell [13][14][15][16]. According to the results of the analysis of recent publications, the Pt/C electrodes, the catalytic ink of which has been prepared without using the Nafion binding polymer, are established to exhibit specific and mass activity in the ORR ~1.8 times higher compared to the electrodes with a deposited catalytic layer, which includes Nafion.…”