Hubert Matondo

Ionic liquids as catalytic “green” reactants and solvents for nucleophilic conversion of fatty alcohols to alkyl halides

We show that ionic liquids such as 1-octyl-3-methylimidazolium bromide or iodide (OMIM/X) make excellent reagents and solvents for the transformation of fatty alcohols into fatty halides in the presence of paratoluene sulfonic acid (PTSA). The conversion used either direct or microwave heating with excellent yields. The ionic liquid was successfully regenerated and reused.

Functionalized Vesicles Based on Amphiphilic Boronic Acids: A System for Recognizing Biologically Important Polyols

We report on a new approach for creating water-soluble functionalized vesicles employing N-alkyl-3-boronopyridinium triflates (alkyl = Me, C12H25, C16H33) as sensors for monosaccharides. The nanoaggregate properties were studied by means of DLS, TEM, high-resolution (1)H NMR, and the solvatochromic dyes Reichardts betaine and Methyl Orange. The vesicles were shown to have 30-200 nm diameters depending on the amphiphile chain length. Diol binding to the vesicles was studied by steady-state fluorescence and UV-vis using Alizarin Red S as a probe in the solution at pH 7.4 in the presence and in the absence of D-glucose and D-fructose. Strong sensing ability of boronic acid functional moieties in the order D-fructose > D-glucose was demonstrated, and apparent binding constants were estimated.

Improved synthesis of azaheteroarylboronic acids using tris-trimethylsilylborate under mild conditions

Abstract A new family of azaheteroarylboronic acids was synthesized with good yields (70% to 75%). The proposed strategy utilizes an improved transmetalation reaction from Grignard azine reagents and tris-trimethylsilylborate, little used until now.

Preparation of a series of N-alkyl-3-boronopyridinium halides and study of their stability in the presence of hydrogen peroxide

AbstractA simple and efficient protocol for the preparation of a series of N-alkyl-3-boronopyridinium salts is described which requires exposure of 3-pyridineboronic acid neopentylglycol ester and corresponding alkyle halide to microwave irradiation followed by boronic ester hydrolysis. The technique employed drastically reduces the reaction time and prevents thermal degradation and the formation of side products. Water solutions of the obtained boronopyridinium salts are shown to be stable at room temperature in wide pH range as well as in the presence of hydrogen peroxide at pH 10.0 for 72 h.