864 research outputs found

    Prevalence and genetic diversity of Trichomonas vaginalis in the general population of Granada and co-infections with Gardnerella vaginalis and Candida species

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    Purpose: Purulent or exudative genitourinary infections are a frequent cause of consultation in primary and specialized healthcare. The objectives of this study were: to determine the prevalence of Trichomonas vaginalis and co-infections with Candida spp. and Gardnerella vaginalis in vaginal secretion; and to use multilocus sequence typing (MLST) to analyse the genetic diversity of T. vaginalis strains. Methodology: The samples were submitted for analysis (n=5230) to a third-level hospital in Granada (Southern Spain) between 2011 and 2014; eight T. vaginalis strains isolated during 2015 were randomly selected for MLST analysis. Culture and nucleic acid hybridization techniques were used to detect microorganisms in the samples. Results: The prevalence of T. vaginalis was 2.4 % between 2011 and 2014, being higher during the first few months of both 2011 and 2012. Among samples positive for T. vaginalis, co-infection with G. vaginalis was detected in 29 samples and co-infection with Candida spp. in 6, while co-infection with all three pathogens was observed in 3 samples. The only statistically significant between-year difference in co-infection rates was observed for T. vaginalis with G. vaginalis due to an elevated rate in 2011. MLST analysis results demonstrated a high genetic variability among strains circulating in our setting. Conclusion: These findings emphasize the need for the routine application of diagnostic procedures to avoid the spread of this sexually transmitted infection

    Recent Developments in Transannular Reactions

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    Transannular reactions have shown a remarkable performance for the construction of polycyclic scaffolds from medium- or large-sized cyclic molecules in an unconventional manner. Recent examples of transannular reactions reported from 2011 have been reviewed, emphasizing the excellent performance of this approach when accessing the target compounds. This review also highlights how this methodology provides an alternative approach to other commonly used strategies for the construction of cyclic entities such as cyclization or cycloaddition reactions.MCIU (FEDER-PID2020-118422-gb-100), Basque Government (IT908-16

    Recent Advances in the Prins Reaction

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    The Prins reaction is a very convenient synthetic platform for the preparation of oxygen-containing heterocyclic compounds, especially tetrahydropyrans and tetrahydrofurans. While this reaction has been extensively used by synthetic chemists since its discovery, the last years have witnessed impressive improvements in its performance and scope and especially in the development of new catalytic and enantioselective versions. This mini-review presents these recent advances through selected representative examples.The authors thank the Spanish Agencia Estatal de Investigacion (FEDER-PID2020-118422-GB-I00) and the Basque Government (Grupos IT1558-22) for financial support

    Desymmetrization of Oxabenzonorbornadienes through Brønsted Acid-Catalyzed Enantioselective (3+2) Cycloaddition with Hydrazones

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    This work presents the desymmetrization of oxabenzonorbornadienes through the (3+2) cycloaddition reaction with hydrazones using a chiral Brønsted acid such as a BINOL-derived phosphoramide. This chiral acid catalyst appears as the most effective mediator for the activation of the hydrazone via hydrazonium cation that reacts in a (3+2) fashion with the oxabenzonorbornadiene as the olefinic counterpart. Under the optimized conditions, the reaction provided selectively exo cycloaddition products in satisfactory yields and moderate stereoselectivities. The scope of the reaction was explored displaying 21 examples of these highly functionalized tetrahydroepoxybenzoindazole compounds. A reaction mechanism is proposed to explain the outcome of the reaction.Grant PID2020-118422GB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future” is gratefully acknowledged. Financial support by the the Basque Government (Grupos IT1558-22) is also gratefully acknowledged

    Asymmetric Dual Enamine Catalysis/Hydrogen Bonding Activation

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    Asymmetric enamine base activation of carbonyl compounds is a well-known and widely used strategy for providing functionalization of organic compounds in an efficient way. The use of solely organic substances, which in most cases are commercially available primary or secondary amines that are easy to obtain, avoids the use of hazardous substances or metal traces, making this type of catalysis a highly convenient methodology from a sustainable point of view. In many cases, the reactivity or the stereoselectivity obtained is far from being a practical and advantageous strategy; this can be improved by using a hydrogen bonding co-catalyst that can help during the activation of one species or by using a bifunctional catalyst that can direct the approximation of reagents during the reaction outcome. In this review, we describe the most efficient methodologies that make use of a dual activation of reagents for performing α-functionalization (enamine activation) or remote functionalization (such as dienamine or trienamine activation) of carbonyl compounds.PID2020-118422GB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future” are gratefully acknowledged together with the Basque Government (Grupos IT1558-22) and the University of the Basque Country (UPV/EHU)

    Ion-pairing catalysis in the enantioselective addition of hydrazones to N-acyldihydropyrrole derivatives

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    We have demonstrated that dihydropyrrole-based enamide derivatives can act as efficient precursors of chiral quaternary N-acyliminium salts under Brønsted acid catalysis that undergo reactions with hydrazones, the latter participating as masked nucleophilic carbonyl group equivalents. The optimized methodology provides a variety of enantiopure α-substituted proline derivatives in excellent yields, being even compatible with disubstituted β-enamides that generate two contiguous stereocentres.Spanish MINECO(FEDER-CTQ201783633-P), the Basque Government (IT908-16) and UPV/EHU (EHUA15/24 and a fellowship to N.Z.

    Catalytic Enantioselective Transannular Morita–Baylis–Hillman Reaction

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    Catalytic and enantioselective approaches to transannular reactions are very limited and mostly are based on chiral Lewis acid catalyzed pericyclic reactions. In this report, we present an efficient and straightforward methodology to access bicyclic carbo- and heterocyclic scaffolds combining different ring sizes through transannular Morita–Baylis–Hillman reaction catalyzed by a chiral enantiopure bifunctional phosphine. The reaction is remarkably wide in scope and enables the use of a variety of medium and large size ketoenone substrates leading to the final products in high yields and providing excellent stereocontrol in the formation of a quaternary stereogenic center at the ring fusion. Moreover, its potential as a general tool in organic synthesis has been highlighted through the accomplishment of the first enantioselective total synthesis of (−)-γ-gurjunene, a sesquiterpene natural product.Spanish MICINN (FEDER-CTQ2017-83633-P 52107-P) and the Basque Government (GruposIT908-16 and fellowship to R. Mato

    An Approach to the Synthesis of a Hepatitis C Virus Inhibitor through a Proline-Catalyzed 1,3-Dipolar Cycloaddition Using Acrolein

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    An efficient and easy protocol for performing 1,3-dipolar cycloaddition using azomethine ylides and acrolein is presented. The reaction catalyzed by d-proline allows the synthesis of C-3 unsubstituted pyrrolidines. The application of this methodology to the synthesis of an advanced intermediate in the preparation of a Hepatitis C virus inhibitor is presented. Final attempts to complete the synthesis of the target inhibitor results in the preparation of its C-4 epimer in good overall yieldSpanish MCIU (FEDER-CTQ2017-83633P y FEDERPID2020-118422-GB-100), Basque Government (Grupos IT908-16

    Organocatalytically Generated Donor − Acceptor Cyclopropanes in Domino Reactions. One-Step Enantioselective Synthesis of Pyrrolo[1,2 ‑ a ]quinolines

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    An easy and straightforward procedure has been developed for the synthesis of highly enantioenriched pyrrolo-[1,2-a]quinolines through a one-pot process that comprises a domino cyclopropane ring opening/aza-Michael/aldol reaction followed by acid-promoted lactamization. The key feature of the synthetic approach relies on the ability of conveniently functionalized cyclopropaneacetaldehydes to undergo organocatalytic activation by a chiral secondary amine that enables the catalytic generation of a donor acceptor cyclopropane. This intermediate has the potential to undergo a ring opening that generates an electrophilic alpha,beta-unsaturated iminium ion that subsequently reacts through the already mentioned domino sequence and in which stereochemical information is very efficiently transferred from the amine catalyst to the final products. Moreover, one of the alkoxycarbonyl moieties can be easily removed by standard hydrolysis/decarboxylation, providing access to the target adducts as single stereoisomers.This research was supported by the Spanish MINECO (FEDER-CTQ2014-52107-P), the Basque Government (Grupos IT328-10), and UPV/EHU (fellowship to E.S. and UFI QOSYC 11/22). Membership in the COST action CM1407 (NatChemDrugs) is also acknowledged

    Favoring Trienamine Activation through Unconjugated Dienals: Organocatalytic Enantioselective Remote Functionalization of Alkenes

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    Unconjugated 2,5-dienals are more reactive substrates than the corresponding fully conjugated a,b,g,dunsaturated aldehydes towards organocatalytic activation through trienamine intermediates. This difference in reactivity has been demonstrated in the Diels–Alder reaction with nitroalkenes, a reaction that proceeds with clean b,eselectivity to afford the final products in high yields and stereoselectivities, the related polyconjugated 2,4-dienals being completely unreactive.Spanish MICINN (CTQ2011–22790 and Juan de la Cierva contract to U.U.), Basque Government (Grupos IT328–10), UPV/EHU (EHUA12/09, UFI QOSYC11/22 and fellowships to G. T. and L.P), COST Action CM090
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