Synthesis of xylitan derivatives and preliminary evaluation of in vitro trypanocidal activity

A series of novel xylitan derivatives derived from xylitol were synthesized using operationally simple procedures. A xylitan acetonide was the key intermediate used to prepare benzoate, arylsulfonate esters and 1,2,3-triazole derivatives of xylitan. These compounds were evaluated for their in vitro anti-Trypanosoma cruzi activity against trypomastigote and amastigote forms of the parasite in T. cruzi-infected cell lineages. Benznidazole was used as positive control against T. cruzi and cytotoxicity was determined in mammalian L929 cells. The arylsulfonate xylitan derivative bearing a nitro group displayed the best activity of all the compounds tested, and was slightly more potent than the reference drug benznidazole. The importance of the isopropylidene ketal moiety was established and the greater lipophilicity of these compounds suggests enhancement in cell penetration2110CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIG473461/2013-7CEX-RED-00010-1

Origin of the diastereoselectivity of the heterogeneous hydrogenation of a substituted indolizine

The authors are grateful to FAPESP for the financial support of this research. The authors also thank FAPESP for the fellowships to R.A.C. (#2018/03910-1) and F.C. (#2013/07600-3 and #2018/02611-3) and for a scholarship to H.S. (#2015/09205-0) and CNPq for a scholarship to L.A.Z. and a research fellowship for F.C, (307840/2014-0, 422890/2016-2 and 301330/2016-2). L.A.Z. also thanks Capes for a scholarship.In this work, the stereoselective heterogeneous hydrogenation of a tetrasubstituted indolizine was studied. Partial hydrogenation products were obtained in three steps from a substituted pyridine-2-carboxaldehyde prepared from commercial pyridoxine hydrochloride. The hydrogenation of the indolizine ring was shown to be diastereoselective, forming trans-6b and cis-9. Theoretical calculations (ab initio and DFT) were used to rationalize the unusual trans stereoselectivity for 6b, and a keto–enol tautomerism under kinetic control has been proposed as the source of diastereoselectivity.Publisher PDFPeer reviewe

Charge Tags For Most Comprehensive Esi-ms Monitoring Of Morita-baylis-hillman (mbh)/aza-mbh Reactions: Solid Mechanistic View And The Dualistic Role Of The Charge Tagged Acrylate.

Neutral and charge tagged reagents were used to investigate the mechanism of the classical Morita-Baylis-Hillman (MBH) reaction as well as its aza-version using mass spectrometry with electrospray ionization (ESI-MS). The use of an acrylate (activated alkene) with a methylimidazolium ion as a charge tag eliminates the requirement for adding acids as ESI(+) additives, which are normally used to favor protonation and therefore detection of reaction partners (reagents, intermediates, and products) by ESI(+)-MS. For both charge tagged reactions (MBH/aza-MBH), most reactants, intermediates, and the final adducts were efficiently detected in the form of abundant doubly and singly charged ions. Characterization of the reactions partners was performed via both tandem mass spectrometry (ESI(+)-MS/MS) and accurate m/z measurements. The charge tagged reactions also showed faster conversion rates when compare to the neutral reaction, indicating a dualistic role for the charge tagged acrylate. It acts as both the reagent and a cocatalyst due to the inherent ionic-coordination nature of the methylimidazolium ion, which stabilizes the zwitterionic intermediates and reagents through different types of coordination ion pairs. Hemiacetal intermediates for the rate-limiting proton transfer step were also intercepted and characterized for both classical and aza-MBH charge tagged reactions.811089-109

Charge Tags for Most Comprehensive ESI-MS Monitoring of Morita–Baylis–Hillman (MBH)/<i>aza</i>-MBH Reactions: Solid Mechanistic View and the Dualistic Role of the Charge Tagged Acrylate

Neutral and charge tagged reagents were used to investigate the mechanism of the classical Morita–Baylis–Hillman (MBH) reaction as well as its <i>aza</i>-version using mass spectrometry with electrospray ionization (ESI-MS). The use of an acrylate (activated alkene) with a methylimidazolium ion as a charge tag eliminates the requirement for adding acids as ESI­(+) additives, which are normally used to favor protonation and therefore detection of reaction partners (reagents, intermediates, and products) by ESI­(+)-MS. For both charge tagged reactions (MBH/<i>aza</i>-MBH), most reactants, intermediates, and the final adducts were efficiently detected in the form of abundant doubly and singly charged ions. Characterization of the reactions partners was performed via both tandem mass spectrometry (ESI­(+)-MS/MS) and accurate <i>m</i>/<i>z</i> measurements. The charge tagged reactions also showed faster conversion rates when compare to the neutral reaction, indicating a dualistic role for the charge tagged acrylate. It acts as both the reagent and a cocatalyst due to the inherent ionic-coordination nature of the methylimidazolium ion, which stabilizes the zwitterionic intermediates and reagents through different types of coordination ion pairs. Hemiacetal intermediates for the rate-limiting proton transfer step were also intercepted and characterized for both classical and <i>aza</i>-MBH charge tagged reactions

Synthesis of Xylitan Derivatives and Preliminary Evaluation of in Vitro Trypanocidal Activity.

Submitted by Nuzia Santos ([email protected]) on 2017-02-14T17:42:02Z No. of bitstreams: 1 ve_Elias_Paula_Synthesis_CPqRR_2016.pdf: 449032 bytes, checksum: 2f8e06eeec6cee1a51be86183a80c8d1 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2017-02-14T17:48:24Z (GMT) No. of bitstreams: 1 ve_Elias_Paula_Synthesis_CPqRR_2016.pdf: 449032 bytes, checksum: 2f8e06eeec6cee1a51be86183a80c8d1 (MD5)Made available in DSpace on 2017-02-14T17:48:24Z (GMT). No. of bitstreams: 1 ve_Elias_Paula_Synthesis_CPqRR_2016.pdf: 449032 bytes, checksum: 2f8e06eeec6cee1a51be86183a80c8d1 (MD5) Previous issue date: 2016Universidade Federal de Ouro Preto. Instituto de Ciências Exatas e Biológicas. Departamento de Quimica. Ouro Preto, MG, BrazilUniversidade Federal de Ouro Preto. Instituto de Ciências Exatas e Biológicas. Departamento de Quimica. Ouro Preto, MG, BrazilUniversidade Federal de Ouro Preto. Instituto de Ciências Exatas e Biológicas. Departamento de Quimica. Ouro Preto, MG, Brazil/Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, BrazilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, BrazilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, BrazilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, BrazilUniversidade Federal de Ouro Preto. Núcleo de Pesquisas em Ciências Biológicas. Laboratorio de Imunopatologia. Ouro Preto, MG, BrazilUniversidade Estadual de Campinas. Instituto de Química. Campinas, SP, BrazilUniversidade Federal de Ouro Preto. Instituto de Ciências Exatas e Biológicas. Departamento de Quimica. Ouro Preto, MG, BrazilUniversidade Federal de Ouro Preto. Instituto de Ciências Exatas e Biológicas. Departamento de Quimica. Ouro Preto, MG, BrazilA series of novel xylitan derivatives derived from xylitol were synthesized using operationally simple procedures. A xylitan acetonide was the key intermediate used to prepare benzoate, arylsulfonate esters and 1,2,3-triazole derivatives of xylitan. These compounds were evaluated for their in vitro anti-Trypanosoma cruzi activity against trypomastigote and amastigote forms of the parasite in T. cruzi-infected cell lineages. Benznidazole was used as positive control against T. cruzi and cytotoxicity was determined in mammalian L929 cells. The arylsulfonate xylitan derivative bearing a nitro group displayed the best activity of all the compounds tested, and was slightly more potent than the reference drug benznidazole. The importance of the isopropylidene ketal moiety was established and the greater lipophilicity of these compounds suggests enhancement in cell penetration

Política criminal y “prevención”

Este libro es el producto de las investigaciones de 2014 que se socializaron en el Congreso Nacional de Política Criminal y "Prevención" en el que se presentaron diferentes posturas y críticas al concepto de "prevención" del delito. La primera parte del libro la hemos denominado "Una crítica al concepto de prevención", en ella se contemplan los siguientes capítulos: "Políticas públicas y 'prevención' en Colombia", en este se confronta una política criminal garantista con una política criminal reactiva; "Prevenciones sobre la prevención: algunas consideraciones desde la criminología", allí se analizan ciertos argumentos clásicos de las políticas de prevención del delito, señala algunos de sus límites y elabora algunas críticas contemporáneas; "Una política criminal desde la garantía de los derechos económicos sociales y culturales: una aproximación al enfoque de género", identifica algunos obstáculos para el logro de una política de prevención del delito desde la garantía de los derechos económicos, sociales y culturales en las mujeres; "La necesidad de una política preventiva verde en Colombia", en el que se desarrolla la tesis según la cual una macropolítica pública de prevención de daños en Colombia debe tener como constituyente central el componente ambiental; y "Programas socioeducativos para resocialización en el contexto penitenciario", este analiza la efectividad de cinco programas socioeducativos en prisión. La segunda parte del libro se titula "Algunos métodos para una política criminal preventiva", en el que encontramos los siguientes capítulos: "Propuesta metodológica para el análisis jurídico-económico del delito: construcción de indicadores auxiliares en la toma de decisiones de política criminal", que propone una metodología para el análisis jurídico-económico del delito; y "Métodos alternativos de solución de conflictos en la política criminal del Estado", el cual aborda la eficacia de la implementación y aplicación obligatoria de la conciliación

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data