One-Pot Transformation of Salicylaldehydes to Spiroepoxydienones via the Adler-Becker Reaction in a Continuous Flow

The Adler-Becker reaction is a useful approach for the oxidative dearomatization of salicylic alcohols to spiroepoxydienones and has been applied in the total synthesis of several natural products. Despite the advantages, the substrate and product instability under the reaction conditions can decrease the reaction efficiency, leading to lower yields. Herein, we report the Adler-Becker reaction in a continuous flow for the transformation of reduced salicylaldehydes into spiroepoxydienones in a one-pot approach. For that, a heterogeneous oxidant based on periodate is developed, leading to an efficient continuous flow process, with higher productivity and shorter reaction times, when compared with batch conditions.

1H NMR Relaxometry and Diffusometry Study of Magnetic and Nonmagnetic Ionic Liquid-Based Solutions: Cosolvent and Temperature Effects

In this work, ¹H NMR relaxometry and diffusometry as well as viscometry experiments were carried out as a means to study the molecular dynamics of magnetic and nonmagnetic ionic liquid-based systems. In order to evaluate the effect of a cosolvent on the superparamagnetic properties observed for Aliquat-iron-based magnetic ionic liquids, mixtures comprising different concentrations, 1% and 10% (v/v), of DMSO-d6 were prepared and studied. The results for both magnetic and nonmagnetic systems were consistently analyzed an suggest that, when at low concentrations, DMSO-d6 promotes more structured ionic arrangements, thus enhancing these superparamagnetic properties. Furthermore, the analysis of temperature and water concentration effects allowed to conclude that neither one of these variables significantly affected the superparamagnetic properties of the studied magnetic ionic liquids.

Ecotoxicological evaluation of magnetic ionic liquids

Although magnetic ionic liquids (MILs) are not yet industrially applied, their continued development and eventual commercial use may lead to their appearance into the aquatic ecosystem through accidental spills or effluents, consequently promoting aquatic contaminations. Furthermore, the deficient information and uncertainty surrounding the environmental impact of MILs could be a major barrier to their widespread industrial application and international registration. Thus, in the present work, a range of cholinium salt derivatives with magnetic properties was synthesized and their ecotoxicity was evaluated towards the luminescent bacteria Vibrio fischeri. The results suggest that all MILs structures tested are moderately toxic, or even toxic, to the bacteria. Furthermore, their toxicity is highly dependent on the structural modifications of the cation, namely the alkyl side chain length and the number of hydroxyethyl groups, as well as the atomic number of the metal anion. Finally, from the magnetic anions evaluated, the [MnCl₄]^2- is the less toxic. In order to improve the knowledge for the prospective design of environmentally safer MILs, it is important to expand this study to other aquatic organisms at different trophic levels.

New low viscous cholinium-based magnetic ionic liquids

This study describes the synthesis of cholinium-based magnetic ionic liquids that are liquid at room temperature and have low toxicity to human cells.

Hydraulic pressures generated in magnetic ionic liquids by paramagnetic fluid/air interfaces inside of uniform tangential magnetic fields

HYPOTHESIS

Magnetic Ionic Liquid (MILs), novel magnetic molecules that form "pure magnetic liquids," will follow the Ferrohydrodynamic Bernoulli Relationship. Based on recent literature, the modeling of this fluid system is an open issue and potentially controversial.

EXPERIMENTS

We imposed uniform magnetic fields parallel to MIL/air interfaces where the capillary forces were negligible, the Quincke Problem. The size and location of the bulk fluid as well as the size and location of the fluid/air interface inside of the magnetic field were varied. MIL properties varied included the density, magnetic susceptibility, chemical structure, and magnetic element.

FINDINGS

Uniform tangential magnetic fields pulled the MILs up counter to gravity. The forces per area were not a function of the volume, the surface area inside of the magnetic field, or the volume displacement. However, the presence of fluid/air interfaces was necessary for the phenomena. The Ferrohydrodynamic Bernoulli Relationship predicted the phenomena with the forces being directly related to the fluid's volumetric magnetic susceptibility and the square of the magnetic field strength. [emim][FeCl4] generated the greatest hydraulic head (64-mm or 910 Pa at 1.627 Tesla). This work could aid in experimental design, when free surfaces are involved, and in the development of MIL applications.

Toxicological evaluation of magnetic ionic liquids in human cell lines

Magnetic ionic liquids (MILs) are new solvents with an interesting broad of applications however their toxicity is still an open issue. In this paper we report the toxicity of [C(8)MIM] and [Choline-C(n)] based magnetic ionic liquids assessed in two human cell lines: normal skin fibroblasts (CRL-1502) and colorectal adenocarcinoma cells (CaCo-2), acquiring this last characteristics of human enterocytes after differentiation. The results showed that [CoCl(4)] and [MnCl(4)] are more prone to generate cytotoxicity.

Toxicity assessment of various ionic liquid families towards Vibrio fischeri marine bacteria

The increasing interest on the application of ionic liquids (ILs) to a wide range of processes and products has been hampered by a lack of toxicological data, mainly in what concerns novel cations, such as guanidinium, phosphonium, and functionalized and non-functionalized imidazolium-based ILs. The present study reports the toxicity of five guanidinium-, six phosphonium, and six imidazolium-based ILs, towards the luminescent marine bacteria Vibrio fischeri. These new results clearly show that guanidinium-, unlike the imidazolium- and phosphonium-based ILs, do not follow the trend of increasing toxicity with the increase in the alkyl chain length. Moreover, the introduction of oxygenated groups on the alkyl chains, such as ether and ester, leads to a decrease of the toxicity of guanidinium and also imidazolium compounds. In what respects the effect of the different cations, it is possible to recognize that the phosphonium-based ILs seem to be more toxic when compared to the analog imidazolium-based ILs (with the same anion and alkyl chains).