Intrinsic gas-phase reactivity of ionized 6-(Oxomethylene)cyclohexa-2,4-dienone: Evidence pointing to its neutral alpha-oxoketene counterpart as a proper precursor of various benzopyran-4-ones and analogues

Despite its unique structure and potential use as an important building block in organic synthesis, the title alpha-oxoketene 1 has been formed mostly under very special conditions as a short-lived species. The reactivity of 1 is, therefore, nearly unexplored. In great contrast, it seemed that its ionized gaseous form 1(center dot+) is stable and easily accessible. In this study, we used multiple-stage pentaquadrupole mass spectrometry to probe the formation of gaseous 1(center dot+) and explore its stability and intrinsic reactivity. With water and methanol, gaseous 1(center dot+) was found to react similarly to solvated 1, which indicates that there is a close parallel between their reactivities. Gaseous 1(center dot+) was also found to react promptly via polar [3 + 2] cycloadditons with various dienophiles including alkenes, alkynes, isocyanates, ketones and esters, thus forming a series of benzopyran-4-ones (flavones, 4-chromanones, 4-chromenones, benzo[1,3]dioxin-4-ones, and analogues) that are common structural units in many natural products. The present availability of 1 at room temperature and the gas-phase findings reported herein for gaseous 1(center dot+) indicate that solvated 1 should undergo many [4 + 2] cycloadditions and functions as a versatile precursor of a variety of biologically active molecules.72165986599

On the species involved in the vaporization of imidazolium ionic liquids in a steam-distillation-like process

45437251725

Intermolecular hydroamination and hydroarylation reactions of alkenes in ionic liquids

Intermolecular hydroamination or hydroarylation reactions of norbornene and cyclohexadiene performed with catalytic amounts of Bronsted or Lewis acid in ionic liquids were found to provide higher selectivity and yields than those performed in classical organic solvents. The ionic liquid increases the acidity of the media and stabilizes ionic intermediates through the formation of supramolecular aggregates. (c) 2006 Elsevier Ltd. All rights reserved.47386775677

1-n-Butyl-3-methylimidazolium tetrachloro-indate (BMI center dot InCl(4)) as a media for the synthesis of biodiesel from vegetable oils

The complex [Sn(3-hydroxy-2-methyl-4-pyrone)(2)(H(2)O)(2)] immobilized in 1-n-butyl-3-methylimidazolium tetrachloro-indate (BMI.InCl(4)) ionic liquid forms an effective biphasic catalytic system for the production of biodiesel from the alcoholysis of soybean oil. ESI-MS experiments during the transesterification reaction indicate that the reaction may proceed through the formation of a cationic species formed through the substitution of one pyrone ligand by one alcohol molecule, followed by coordination of the carboxylate compound to tin. The adduct thus formed undergoes transesterification with liberation of the catalytic active species. (c) 2007 Elsevier Inc. All rights reserved.249215416

Multiply charged (Di-)radicals

47115115

Charge-tagged N-heterocyclic carbenes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The interception, formation and characterization of the first stable, long lived charge-tagged N-heterocyclic carbenes of the general type 4(x+) (x = 1-3) and analogues is reported. Via ESI(+)-MS of solutions of bromine salts of doubly, triply and quadruply charged imidazolium ion IL (3. Br-n, n = 2-4), the isolated 4(x+) as well as charged aggregates [3.Br(n-x)](x+) likely to be participating in the [3.Br(n-x)](x+) reversible arrow 4(x+) + HBr solution equilibrium could be transferred and characterized in the gas phase. Mimicking the solution equilibrium, the gaseous [3.Br(n-x)](x+) were found to dissociate nearly exclusively via HBr loss during thermal activation via collisions to form gaseous 4(x+), which were found to add to acrolein and acetone.117378Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)INCT-MCTFAPERGSConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Monitoring of beta-Blockers Ozone Degradation via Electrospray Ionization Mass Spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The structures of intermediate products of ozone degradation of different pharmaceutical compounds have been studied. Under the conditions employed, complete ozone degradation of nadolol was achieved after 100 min. The degradation products obtained in aqueous solution were characterized by electrospray ionization mass (and tandem mass) spectrometry (ESI-MS and ESI-MS/MS). The proposed mechanism for degradation, ozone attacks at the aniline amino group giving rise to nitro compounds and further degradation occurs via a series of oxidative processes. Continuous online monitoring by ESI-MS(/MS) with high accuracy mass measurements showed that ozone degradation of atenolol (ATE) and acebutolol (ACE) occurs via mechanisms similar to that of nadolol.225919928Proyecto Bicentenario de Ciencia y Tecnologia [PSD-16]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FONDECYT [1085308]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Proyecto Bicentenario de Ciencia y Tecnologia [PSD-16]FONDECYT [1085308

Natural AD-like neuropathology in Octodon degus: Impaired burrowing and neuroinflammation

Alzheimer’s disease (AD) is the most common cause of dementia, affecting more than 36 million people worldwide. Octodon degus, a South American rodent, has been found to spontaneously develop neuropathological signs of AD, including amyloid-β (Aβ) and tau deposits, as well as a decline in cognition with age. Firstly, the present work introduces a novel behavioral assessment for O. degus - the burrowing test - which appears to be a useful tool for detecting neurodegeneration in the O. degus model for AD. Such characterization has potentially wide-ranging implications, because many of these changes in species-typical behaviors are reminiscent of the impairments in activities of daily living (ADL), so characteristic of human AD. Furthermore, the present work characterizes the ADlike neuropathology in O. degus from a gene expression point of view, revealing a number of previously unreported AD biomarkers, which are found in human AD: amyloid precursor protein (APP), apolipoprotein E (ApoE), oxidative stressrelated genes from the NFE2L2 and PPAR pathway, as well as pro-inflammatory cytokines and complement proteins, in agreement with the known link between neurodegeneration and neuroinflammation. In summary, the present results confirm a natural neuropathology in O. degus with similar characteristics to AD at behavioral, cellular and molecular levels. These characteristics put O. degus in a singular position as a natural rodent model for research into AD pathogenesis and therapeutics against AD.Research was conducted under permit No. 5193 issued by the Servicio Agrícola y Ganadero, Chile, with the supervision of the Ethics Committee of the Faculty of Sciences, Universidad de Chile