Green, new and efficient tandem oxidation and conversion of aryl alcohols to 2,4,6-triarylpyridines promoted by [HMIm]NO3-[BMIm]BF4 as a binary ionic liquid

4,6-Dihydroxysalicylic Acid-Catalyzed Oxidative Condensation of Benzylic Amines and Aromatic Ketones for the Preparation of 2,4,6-Trisubstituted Pyridines and Its Application to Metal-Free Synthesis of G-Quadruplex Binding Ligands

4,6-Dihydroxysalicylic acid was activated under air to catalyze the one-pot oxidative condensation reaction of benzylamines with acetophenones in the presence of BF₃·Et₂O, affording 2,4,6-trisubstituted pyridines in yields of 59-91%. During this metal-free oxidative condensation reaction, the benzylamines not only provided the aryl moiety at the 4-position of the pyridines but also acted as the nitrogen donor. This method can be applied to the metal-free synthesis of G-quadruplex binding ligands by the sequential addition of 4-chlorobutyryl chloride and pyrrolidine to the reaction system of the 2,4,6-trisubstituted pyridine synthesis.

Ionic liquid mixtures-variations in physical properties and their origins in molecular structure

In order to explore the various possible property trends in ionic liquid mixtures, five different ionic liquids were mixed with N-methyl-N-propylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([C3mpyr][NTf2]), and the viscosities, excess molar volumes, ionic conductivities, and phase diagrams of the mixtures were determined over a range of temperatures. In a number of the mixtures the crystallization of both components was completely suppressed and no melting point was observable. Such mixtures of similar ionic liquids thus have potential for use in low-temperature applications by extending the liquid range to T(g). The molar conductivities and viscosities are described as approximating predictable or "simple" mixing behaviors, while excess molar volumes were found to show a variety of mixing and nonideal mixing effects. Mixture equations for viscosity and conductivity are discussed and analyzed. An immiscibility window was observed in the trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P(6,6,6,14)][NTf2]) in the [C3mpyr][NTf2] system in the [C3mpyr][NTf2]-rich region. Unusual physical properties are exhibited by miscible compositions near the demixing line. These compositions are described as [P(6,6,6,14)][NTf2]-like, even up to 0.5 mol fraction of [C3mpyr][NTf2].

Solvent-free, one-pot synthesis of 2,4,6-triarylpyridines using trichloroisocyanuric acid or N-bromosuccinimide as a novel and neutral catalyst

A simple and benign protocol has been explored for the preparation of 2,4,6-triarylpyridines by a one-pot reaction between aryl aldehydes, enolizable ketones and ammonium acetate in the presence of N-bromosuccinimide or trichloroisocyanuric acid as green and neutral catalysts. The reactions proceed smoothly at 130 °C under solvent-free conditions to provide 2,4,6-triarylpyridines in good yields.