Brønsted Acidic Ionic Liquid Accelerated Halogenation of Organic Compounds with N-Halosuccinimides (NXS)

Abstract

The Brønsted-acidic ionic liquid 1-methyl-3-(4-sulfobutyl)imidazolium triflate [BMIM(SO3H)][OTf] was demonstrated to act efficiently as solvent and catalyst for the halogenation of activated organic compounds with N-halosuccinimides (NXS) under mild conditions with short reaction times. Methyl aryl ketones were converted into α-halo and α,α-dihaloketones, depending on the quantity of NXS used. Ketones with activated aromatic rings were selectively halogenated, however in some cases mixtures of α-halogenated ketone and ring-halogenated ketones were obtained. Activated aromatics were regioselectively ring halogenated to give mono- and dihalo-substituted products. The [BMIM(SO3H)][OTf] ionic liquid (IL-A) was successfully reused eight times in a representative monohalogenation reaction with no noticeable decrease in efficiency. An effective halogenation scale-up in this IL is also presented. The reactivity trend and the observed chemo- and regioselectiivities point to an ET process in these IL-promoted halofunctionalization reactions.

Nurses' preparedness to care for women exposed to Intimate Partner Violence: a quantitative study in primary health care

“…Health problems associated with IPV are often treated as problems in their own right rather than as the result of IPV [20,21]. Consequently, when the abuse remains undetected, the women may experience a secondary victimisation and the suffering of care [22,23]. Results from studies have shown that healthcare staff often lack relevant knowledge, are uncertain about how to ask, are concerned about breaching the woman's integrity, or are unsure about which intervention should be implemented once IPV is confirmed [18,24-27].…”

Rapamycin-Induced Apoptosis in HGF-Stimulated Lens Epithelial Cells by AKT/mTOR, ERK and JAK2/STAT3 Pathways

“…As we know, apoptosis is induced via two main routes involving either the mitochondria or the activation of death receptors. The mitochondrial pathway is activated by a wide range of signals and involves the release of proteins (including cytochrome c) from the mitochondrial membrane space [28,29,35,36]. Our results indicated that the expression of cytochrome c and the activity of cleaved caspase-3 were greatly increased after rapamycin treatment in the presence of HGF, which suggested that the apoptosis was induced by engaging mitochondrial pathway, and catalytic activation of the caspases [29].…”

“…In the past few years, a new strategy was proposed to remove the residual LECs by inducing apoptosis [16]. Previous studies have shown that over expression of Bax or procaspase-3 is capable of inducing therapeutic programmed cell death of residual LECs in vitro and in vivo and preventing PCO in a rabbit model [28,29]. Recent studies have concentrated on the cytokines involved in the development of PCO that were produced by the LECs themselves and believed to play an important role [3,30,31,32,33,34].…”

Esterification of Aryl/Alkyl Acids Catalysed by N-bromosuccinimide under Mild Reaction Conditions

“…In our continuous pursuit of sustainable synthetic protocols [ 33 , 34 , 35 , 36 , 37 ], including those where NXSs are used as reagents [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ], we now report and introduce the use of substoichiometric amounts of these compounds as mediators for efficient and selective comprehensive metal-free direct esterification of carboxyl functionality in organic molecules under neat reaction conditions ( Scheme 1 ).…”