This article describes the synthesis of six palladium complexes derived from three bis‐imines or their corresponding amines. These metallic complexes were evaluated as promising catalysts for Heck reaction. The potential of such organometallic catalysts was investigated using the coupling between bromobenzene and styrene as reaction model, involving evaluation of ranging bases, different solvents, reaction times and the quantity of palladium catalyst. Our findings indicate that the complexes obtained from amines are better than those from imines. Dimethyl acetamide (DMA) and sodium carbonate were the best solvents and bases in the Heck coupling reaction, respectively. In summary, these Schiff bases and corresponding amines provide an innovative opportunity to develop new catalytic systems for the Heck reaction.
Abstract:Previous studies have shown that the association of the drug meglumine antimoniate (MA) with β-cyclodextrin can improve its bioavailability by the oral route. In this work, ribose and maltose were investigated for their ability to form mixed or association complexes with MA, release MA and modulate the serum levels of Sb after oral administration in mice. Analysis of the MA/ribose composition by high performance liquid chromatography coupled to mass spectrometry (LCMS-IT-TOF) revealed the presence of mixed meglumine-Sb-ribose and Sb-ribose complexes. Analysis of the MA/maltose composition suggested the formation of MA-maltose association compounds. Circular dichroism characterization of these compositions following dilution in water at 37 °C suggested a partial and slow dissociation of the association compounds. When the MA/ribose composition was administered orally and compared to MA, the serum concentration of Sb was significantly lower after 1 h and greater after 3 h. On the other hand, the MA/maltose composition showed similar serum Sb concentration after 1 h and higher level of Sb after 3 h, when compared to MA. In conclusion, the present study has demonstrated the formation of mixed or association complexes of MA with sugars, such as maltose and ribose, which promoted sustained serum level of Sb after oral administration.
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