The Synthesis of 2'-Hydroxychalcones under Ball Mill Conditions and Their Biological Activities.

Chalcones are polyphenols that belong to the flavonoids family, known for their broad pharmacological properties. They have thus attracted the attention of chemists for their obtention and potential activities. In our study, a library of compounds from 2'-hydroxychalcone's family was first synthesized. A one-step mechanochemical synthesis via Claisen-Schmidt condensation reaction under ball mill conditions was studied, first in a model reaction between a 5'-fluoro-2'-hydroxyacetophenone and 3,4-dimethoxybenzaldehyde. The reaction was optimized in terms of catalysts, ratio of reagents, reaction time, and influence of additives. Among all assays, we retained the best one, which gave the highest yield of 96% when operating in the presence of 1 + 1 eq. of substituted benzaldehyde and 2 eq. of KOH under two grinding cycles of 30 min. Thus, this protocol was adopted for the synthesis of the selected library of 2'-hydroxychalcones derivatives. The biological activities of 17 compounds were then assessed against Plasmodium falciparum, Leishmania donovani parasite development, as well as IGR-39 melanoma cell lines by inhibiting their viability and proliferation. Compounds 6 and 11 are the most potent against L. donovani, exhibiting IC50 values of 2.33 µM and 2.82 µM, respectively, better than the reference drug Miltefosine (3.66 µM). Compound 15 presented the most interesting antimalarial activity against the 3D7 strain, with IC50 = 3.21 µM. Finally, chalcone 12 gave the best result against IGR-39 melanoma cell lines, with an IC50 value of 12 µM better than the reference drug Dacarbazine (IC50 = 25 µM).

Characterization of surface properties of chitosan/bentonite composites beads by inverse gas chromatography.

Chitosan/bentonite (CSBt) composites beads were prepared by dropwise of a solution containing chitosan and bentonite to an alkaline NaOH solution. Fourier Transform Infrared Spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, XPS and Brunauer-Emmett-Teller BET analysis have been used to provide new insights on the composition and morphology of CSBt composites beads surface. In this study, inverse gas chromatography (IGC) was implemented to characterize physico-chemical properties of CSBt composites surface. IGC at infinite dilution (IGC-ID) was used to understand the effect of CS on dispersive component of the surface energy of the bentonite. The increasing amount of CS leads to significantly decrease of Bt γsd emphasizing the Bt coating with CS. The IGC at finite concentration (IGC-FC) was also implemented allowing us to reach several parameters such as: specific surface area with organic probes and the distribution functions of the adsorption energy sites on the solid surface. In this case, the most significant decreases were observed in the specific surface area obtained with the octane and isopropanol probes. The distribution function of the adsorption energy sites obtained with isopropanol revealed the decrease in the number of the high energy sites with increase of CS/Bt mass ratio.

Study of the interaction polybutadiene/fillers using inverse gas chromatography.

In this study, the coupling of IGC-ID analysis and carbon blacks impregnation with increasing ratios of polymer allow us to highlight the affinity of the polymer to the solid surface. The variations of the dispersive component of the surface energy and of the nanomorphology index are monitored versus the degree of carbon black impregnation. A clear correlation between the decrease in the dispersive component of the surface energy and the increase in the nanomorphological index is observed. The PBu macromolecules shield progressively the slot shaped sites on the carbon blacks surface. IGC reveals clear differences in surface properties between CB of different grades.

Coupling of inverse gas chromatography at infinite dilution (IGC-ID) with a controlled modification of a solid surface.

This paper presents a new method for studying the surface of a heterogeneous solid by inverse gas chromatography at infinite dilution (IGC-ID). After saturating the high-energy sites by impregnation with a suitable polymer, the chromatographic probes visit the low energy sites, which are not visible by conventional IGC-ID. This method has been used to study the two types of surface of talc: lateral and basal surfaces. In the second part of the paper the influence of the structure of the polymer on the impregnation is examined. In particular it is shown that a polymer with a linear structure is more able to fit a rough surface than is a branched or a cyclic polymer.