Iron catalysts with N-ligands for carbene transfer of diazo reagents

Transition-metal-catalyzed carbene transfer reactions, involving diazo compounds and their precursors, are powerful tools for creating new C-C bonds. Depending on the involved catalytic system, the carbene insertion can efficiently be driven towards a specific functional group for the synthesis of a wide portfolio of fine chemicals. The present report is focused on the catalytic activity of iron catalysts in promoting alkene cyclopropanations, C-H and X-H (X = N, O, S, Se, Si, Sn, Ge) functionalizations. Porphyrin, porphyrinoid and non-heme iron complexes are discussed by analyzing experimental studies and theoretical calculations performed for proposing reaction mechanisms. The catalytic activity of artificial iron biocatalysts is also briefly reported in order to underline the similarities and differences between reaction mechanisms mediated by modified biocatalysts and synthetic catalysts. This review summarizes the achievements made in this field since 2006

Porphyrin-based homogeneous catalysts for the CO 2 cycloaddition to epoxides and aziridines

The direct insertion of carbon dioxide (CO2) into three-membered rings, such as epoxides and aziridines, represents a relevant strategy to obtain cyclic carbonates and oxazolidinones, which are two useful classes of fine chemicals. The synthesis of these compounds can be efficiently catalyzed by a combination of metal porphyrin complexes and various co-catalysts in homogeneous systems. The catalytic efficiency of these systems is discussed herein by taking into account both the characteristics of the metals and the nature of the co-catalysts, either when used as two-component systems or when combined in bifunctional catalysts. Moreover, mechanistic proposals of the CO2 cycloaddition processes are reported to provide a rationale of catalytic cycles in order to pave the way for designing more active and efficient catalytic procedures

Una arquitectura basada en la web semántica para la gestión de versiones de familias de producto

El objetivo principal del trabajo es presentar el desarrollo de una arquitectura y su implementación en una aplicación prototipo que permite la utilización de una ontología de gestión de versiones para la integración y ges-tión unificada de variantes y versiones de Familias de Productos. Se propone un modelo de arquitectura compuesto de 3 módulos que se comunican entre sí cumpliendo funciones específicas, haciendo uso de diversas herramientas de la Web Semántica. La herramienta propuesta puede ser utilizada para lograr la gestión de la variabilidad en el tiempo y en el espacio de Familias de Producto en diversos tipos de industrias. En particular, en este artículo se introduce su aplicación, para la gestión de versiones y variantes, de una Familia de teléfonos celulares.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Selective, non-covalent conjugation of synthetic peptides with recombinant proteins mediated by host-guest chemistry.

The combination of potent chemical moieties with biologically active proteins is key to some of today's most innovative therapeutic drugs. In order to obviate any chemical modification of the proteins, we present a novel and powerful strategy for the selective conjugation of recombinant protein domains with synthetically derived peptides via a cucurbit[8]uril host-guest chemistry approach.We thank Alexandra Rieck, Isabelle Sermadiras, Benjamin Kemp and Jennifer Spooner for help with the expression and purification of the Fc and Tn3 domains, Jefferson Revell and Jacky Metcalfe for help with the synthesis of modified peptides and Christel Veyssier for help with the light scattering experiments. RJG was supported by the MedImmune postdoctoral program. SS was supported by ERC Starting Investigator grant ASPiRe (No. 240629).This is the final version of the article. It first appeared from Royal Society of Chemistry via http://dx.doi.org/10.1039/C6CC00405

Modelo conceptual para la integración de PRONTO con el estándar ISO 15926

En el presente trabajo se propone un modelo conceptual basado en el estándar ISO 15926, con el fin de extenderlo y hacer explícita la representación de variantes de productos propuestos por PRONTO. Esta extensión permitirá introducir el modelo de producto en un entorno colaborativo, donde los sistemas de información son capaces de intercambiar información de productos con otros sistemas. La interoperabilidad de sistemas tiende a aumentar la consistencia de modelos ante la diversidad de interpretaciones. Por ello, la propuesta introduce nuevos elementos al modelo de datos del estándar, para tener un mapeo completo con los conceptos de PRONTO. Además, se representa en el tiempo los cambios producidos en la información de producto, a través del enfoque 4D.Sociedad Argentina de Informática e Investigación Operativ

Nickel (0) complexes as promising chemosensors for detecting the “cork taint” in wine

2,4,6-Trichloroanisole (TCA) is well recognized as one of the most responsible molecules of cork taint, an organoleptic defect of wine which represents a serious problem for wine industries. Up to now, very few examples of TCA-biosensors have been developed and we report herein a promising nickel (0) complex that can be employed as chemosensor for the TCA detection in cork stoppers. Among the three Ni (0) complexes studied in this work, complex Ni(0)(BINAP)(η2-PhCN) (2) showed the best reactivity towards pure TCA affording the oxidative addition product 4 in four hours at room temperature. Compound 4 represents an appealing probe for the indirect quantification of TCA due to the presence of the characteristic UV-adsorption band at 444 nm. Statistical studies on real samples confirmed that the presence of TCA can be detected by employing UV-Visible spectroscopy, as demonstrated by PCA analyses which allowed distinguishing TCA-contaminated samples from non-contaminated ones. Even if the present study has to be considered a preliminary approach for the realization of a chemosensor usable in real systems, the here reported Ni (0)-based sensing procedure represents the first examples of TCA chemical detection

Initiating discourse on the (multi?) directionality of the Mainland Southeast Asian Bronze Age transition

International audienceDiscourse on early Southeast Asian metallurgy has been dominated by theories on how and when the technologyarrived from present-day China, with little to no discussion about how and when metallurgy dispersed withinSoutheast Asia. This situation is a logical result of how interest in prehistoric metallurgy and subsequentarchaeometallurgical investigation has developed in the region, particularly with respect to dating controversies andmajor geographical data biases. In this paper I propose a new and testable mid-late 2nd to early-1st millennium BCsouth-to-north and partly maritime/up-river dispersion model that seeks to complement the extra-regional theoriesfor metallurgy’s generally north-to-south terrestrial/down-river arrival in Mainland Southeast Asia

A Metal-Free Synthesis of N-Aryl Oxazolidin-2-Ones by the One-Pot Reaction of Carbon Dioxide with N-Aryl Aziridines

The cost-effective TPPH2/TBACl-catalyzed (TPPH2=dianion of tetraphenyl porphyrin; TBACl=tetrabutyl ammonium chloride) carbon dioxide cycloaddition to N-aryl aziridines was successful in synthesizing N-aryl oxazolidin-2-ones. A catalytic tandem reaction was also developed, in which N-aryl aziridines were initially synthesized and then reacted with carbon dioxide without being purified. The procedure occurred with a very high atom economy, molecular nitrogen being the only by-product of the entire tandem process. In addition, the mechanism of catalytic cycle was investigated by DFT calculations. (Figure presented.)

Selective, non-covalent conjugation of synthetic peptides with recombinant proteins mediated by host–guest chemistry

The combination of potent chemical moieties with biologically active proteins is key to some of today's most innovative therapeutic drugs. In order to obviate any chemical modification of the proteins, we present a novel and powerful strategy for the selective conjugation of recombinant protein domains with synthetically derived peptides via a cucurbit[8]uril host-guest chemistry approach.We thank Alexandra Rieck, Isabelle Sermadiras, Benjamin Kemp and Jennifer Spooner for help with the expression and purification of the Fc and Tn3 domains, Jefferson Revell and Jacky Metcalfe for help with the synthesis of modified peptides and Christel Veyssier for help with the light scattering experiments. RJG was supported by the MedImmune postdoctoral program. SS was supported by ERC Starting Investigator grant ASPiRe (No. 240629).This is the final version of the article. It first appeared from Royal Society of Chemistry via http://dx.doi.org/10.1039/C6CC00405