Brønsted Acid-Catalyzed Cascade Reactions Involving 1,2-Indole Migration

A cascade reaction of indoles with propargylic diols involving an unprecedented metal-free 1,2-indole migration onto an alkyne is here described. DFT calculations support a mechanism consisting in a concerted nucleophilic attack of the indole nucleus with loss of water followed by the 1,2-migration and subsequent Nazarov cyclization. This Brønsted acid-catalyzed protocol affords indole-functionalized benzofulvene derivatives in high yields.Junta de Castilla y León(BU237U13) and Ministerio de Economía y Competitividad (MINECO) and FEDER (CTQ2013-48937-C2-1P and 2-P

Rational Design of Efficient Environmental Sensors: Ring-Shaped Nanostructures Can Capture Quat Herbicides

The viability of using [n]-cycloparaphenylenes (CPPs) of different sizes to encapsulate diquat (DQ) pesticide molecules has been tested analyzing the origin of the host–guest interactions stabilizing the complex. This analysis provides rational design capabilities to construct ad hoc capturing systems tailored to the desired pollutant. All CPPs considered (n = 7–12) are capable of forming remarkably stable complexes with DQ, though [9]-CPP is the best candidate, where a fine balance is established between the energy penalty due to the deformation + repulsion of the pesticide molecule inside the cavity (larger in smaller CPPs) and the maximization of the favorable dispersion, electrostatic and induction contributions (which also decrease in larger rings). These encouraging results prompted us to evaluate the potential of using Resonance Raman spectroscopy on nanohoop complexes as a tool for DQ sensing. The shifts observed in the vibrational frequencies of DQ upon complexation allow us to determine whether complexation has been achieved. Additionally, a large enhancement of the signals permits a selective identification of the vibrational modesThe authors thank the Centro de Supercomputación de Galicia (CESGA) for the generous allocation of computer time. Ministerio de Economía y Competitividad (MINECO, PCTQ2016-75023-C2-2-P) and Consellería de Cultura, Educación e Ordenación Universitaria e da Consellería de Economía, Emprego e Industria (Axuda para Consolidación e Estruturación de unidades de investigación competitivas do Sistema Universitario de Galicia, Xunta de Galicia ED431C 2017/17) are also acknowledged. Á.V.V. is grateful to the Universidade de Vigo for a predoctoral fellowshipS

Synthesis of diverse indole-containing scaffolds by gold(I)-catalyzed tandem reactions of 3-propargylindoles initiated by 1,2-indole migrations: scope and computational studies

Similar to propargylic carboxylates and sulphides, 3- propargylindoles undergo 1,2-indole migrations under cationic gold(I)- catalysis. The intermediate Aucarbenoid complex may evolve through different pathways depending on the substituents at the propargylic and terminal positions of the alkyne moiety. Thus, 3-indenylindole derivatives were easily obtained through formal iso- Nazarov or Nazarov cyclizations. DFT computations support the formation of an alkylidenecyclopropane intermediate that undergoes aura-iso-Nazarov or aura-Nazarov cyclizations upon torquoselective ring opening. In addition, 3-dienylindoles could be accessed when none of the referred pathways were accessible and so the intermediate Au-carbenoid complex evolved via a 1,2-CH insertion reaction. We have also demonstrated that the final products can be obtained in a one-pot protocol from easily available propargylic alcohols and indolesMEC/FEDER (CTQ2007-61436/BQU) and Junta de Castilla y León (BU021A09) for financial support. We are also grateful to MEC (FPU predoctoral fellowship to D.M., “Young Foreign Researchers” contract (SB2006-0215) to M.G., “Ramón y Cajal” contract to M.A.F.-R., and “Juan de la Cierva” contract to P.G.-G.) and Fundación Ramón Areces (predoctoral fellowship to A.G.P.).This is the peer reviewed version of the following article: Sanz, R., Miguel, D., Gohain, M., García-García, P., Fernández-Rodríguez, Manuel A., González-Pérez, A., Nieto-Faza, O., de Lera, Ángel R. and Rodríguez, F. (2010), Synthesis of Diverse Indole-Containing Scaffolds by Gold(I)-Catalyzed Tandem Reactions of 3-Propargylindoles Initiated by 1,2-Indole Migrations: Scope and Computational Studies. Chem. Eur. J., 16: 9818–9828. doi:10.1002/chem.201001162, which has been published in final form at doi:10.1002/chem.201001162. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archivin

Gold(i)-catalyzed nucleophilic cyclization of β-monosubstituted o-(alkynyl)styrenes: a combined experimental and computational study

The stereospecific gold(I)-catalyzed nucleophilic cyclization of β-monosubstituted o-(alkynyl)styrenes to produce C-1 functionalized 1H-indenes including challenging substrates and nucleophiles, such as β-(cyclo)alkyl-substituted o-(alkynyl)styrenes and a variety of alcohols as well as selected electron-rich aromatics, is reported. DFT calculations support the stereochemical outcome of the process that involves the formation of a key cyclopropyl gold carbene intermediate through a regiospecific 5-endo cyclization.Ministerio de Economía y Competitividad (MINECO) and FEDER (CTQ2016-75023-C2-1-P and 2-P), and Junta de Castilla y León and FEDER (BU291P18) and Xunta de Galicia (ED431C 2017/70 and ED431E 2018/07

Factors influencing plasma transfusion practices in paediatric intensive care units around the world

Background and Objectives Plasma transfusions are a frequent treatment worldwide, but many studies have reported a wide variation in the indications to transfuse. Recently, an international paediatric study also showed wide variation in frequency in the use of plasma transfusions: 25% of the centres transfused plasma to >5% of their patients, whereas another 25% transfused plasma to <1% of their patients. The objective of this study was to explore the factors associated with different plasma transfusion practices in these centres. Materials and Methods Online survey sent to the local investigators of the 101 participating centres, in February 2016. Four areas were explored: beliefs regarding plasma transfusion, patients’ case‐mix in each unit, unit's characteristics, and local blood product transfusion policies and processes. Results The response rate was 82% (83/101). 43% of the respondents believed that plasma transfusions can arrest bleeding, whereas 27% believe that plasma transfusion can prevent bleeding. Centres with the highest plasma transfusion rate were more likely to think that hypovolaemia and mildly abnormal coagulation tests are appropriate indications for plasma transfusions (P = 0·02 and P = 0·04, respectively). Case‐mix, centre characteristics or local transfusion services were not identified as significant relevant factors. Conclusion Factors influencing plasma transfusion practices reflect beliefs about indications and the efficacy of transfusion in the prevention and management of bleeding as well as effects on coagulation tests. Educational and other initiatives to target these beliefs should be the focus of research