1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF3: the case of alkyne hydration. Chemistry vs electrochemistry

In order to replace the expensive metal/ligand catalysts and classic toxic and volatile solvents, commonly used for the hydration of alkynes, the hydration reaction of alkynes was studied in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm-BF4) adding boron trifluoride diethyl etherate (BF3·Et2O) as catalyst. Different ionic liquids were used, varying the cation or the anion, in order to identify the best one, in terms of both efficiency and reduced costs. The developed method was efficaciously applied to different alkynes, achieving the desired hydration products with good yields. The results obtained using a conventional approach (i.e., adding BF3·Et2O) were compared with those achieved using BF3 electrogenerated in BMIm-BF4, demonstrating the possibility of obtaining the products of alkyne hydration with analogous or improved yields, using less hazardous precursors to generate the reactive species in situ. In particular, for terminal arylalkynes, the electrochemical route proved to be advantageous, yielding preferentially the hydration products vs the aldol condensation products. Importantly, the ability to recycle the ionic liquid in subsequent reactions was successfully demonstrated.

An ultrasound assisted, ionic liquid-molecular iodine synergy driven efficient green synthesis of pyrrolobenzodiazepine-triazole hybrids as potential anticancer agents

Herein, we report an efficient and eco-friendly, ultrasound assisted synthetic strategy for the construction of diversified pyrrolobenzodiazepine-triazole hybrids, which are potentially pharmaceutically important scaffolds, via a domino reaction involving intermolecular electrophilic substitution followed by intramolecular Huisgen 1,3-dipolar azide-alkyne cycloaddition. The USP of the reported protocol is the use of benign and inexpensive, recyclable molecular iodine-ionic liquid synergistic catalytic system cum reaction media for achieving the synthesis. The other salient features of this method are the use of mild reaction conditions, high yield and atom economy, operational simplicity, broad substrate scope and easy workup and purification. All the synthesized compounds were evaluated for in vitro anti-proliferative activity against various cancer cell lines. From among the synthesized title compounds, 9,9-dimethyl-8-phenyl-9H-benzo [b]pyrrolo [1,2-d][1,2,3]triazolo[5,1-g][1,4]diazepine (7) was found most to be the most active compound exhibiting IC₅₀ value of 6.60, 5.45, 7.85, 11.21, 12.24, 10.12, and 11.32 µM against MCF-7, MDA-MB-231, HeLa, SKOV-3, A549, HCT-116 and DLD-1 cell lines, respectively. Further the compounds were found to be non-toxic against normal human embryonic kidney (HEK-293) cell line.

Latest developments on the synthesis of bioactive organotellurium scaffolds

This review deals with the latest developments on the synthesis of biologically promising organotellurim scaffolds reported during last two decades.

One-pot multi-component synthesis of diverse bioactive heterocyclic scaffolds involving 6-aminouracil or its N-methyl derivatives as a versatile reagent

The present review summarizes all the multi-component reaction strategies reported during last two decades for the synthesis of diverse bioactive heterocyclic scaffolds involving 6-aminouracil or its N-methyl derivatives.

Facile Preparation of Aryl Nitriles from Aryl Aldehydes in PEG-DME 250

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A facie and efficient method for one-pot transformation of aryl aldehydes to aryl nitriles using hydroxylamine hydrochloride and phosphorus tribromide in PEG-DME 250 is reported. The conversion of various aryl aldehydes to the corresponding aryl nitriles occurred smoothly in high yields under the present reaction conditions.

Excess chemical potential of thiophene in [C4MIM] [BF4, Cl, Br, CH3COO] ionic liquids, determined by molecular simulations

The excess chemical potential of thiophene in imidazolium-based ionic liquids [C₄mim][BF₄], [C₄mim][Cl], [C₄mim][Br], and [C₄mim][CH₃COO] were determined by means of molecular dynamics in conjunction with free energy perturbation techniques employing non-polarizable force fields at 300 K and 343.15 K. In addition, energetic and structural analysis were performed such as: interaction energies, averaged noncovalent interactions, radial, and combined distribution functions. The results from this work revealed that the ionic liquids (ILs) presenting the most favorable excess chemical potentials ([C₄mim][BF₄], [C₄mim][CH₃COO]) are associated with the strongest energetic interaction between the thiophene molecule and the ionic liquid anion, and with the weakest energetic interaction between the thiophene molecule and the ionic liquid cation.

Excess chemical potential of thiophene in imidazolium-based ionic liquids [C₄mim][BF₄], [C₄mim][Cl], [C₄mim][Br], and [C₄mim][CH₃COO] determined by molecular simulations.

A concerted addition mechanism in [Hmim]Br-triggered thiol–ene reactions: a typical “ionic liquid effect” revealed by DFT and experimental studies

The π⁺–π and H-bond interactions between [Hmim]Br and substrates promote a special one-step addition mechanism in thiol–ene reactions.