30 research outputs found
Straightforward Assembly of Benzoxepines by Means of a Rhodium(III)-Catalyzed C–H Functionalization of o-Vinylphenols
This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Chemical Biology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see: https://pubs.acs.org/doi/10.1021/ja410538wReadily available o-vinylphenols undergo a formal (5 + 2) cycloaddition to alkynes when treated with catalytic amounts of [Cp*RhCl2]2 and Cu(OAc)2. The reaction, which involves the cleavage of the terminal C–H bond of the alkenyl moiety, generates highly valuable benzoxepine skeletons in a practical, versatile, and atom-economical manner. Using carbon monoxide instead of an alkyne as reaction partner leads to coumarin products which formally result from a (5 + 1) cycloadditionWe are thankful for the financial support provided by the
Spanish Grants (SAF2010-20822-C02 and CSD2007-00006
Consolider Ingenio 2010), the ERDF and the Xunta de Galicia
Grants GRC2010/12, GR2013-041, INCITE09 209084PR and
EM2013/036. M.G thanks Xunta de Galicia for a Parga Pondal
contractS
Rhodium-Catalyzed (5+1) Annulations Between 2-Alkenylphenols and Allenes: A Practical Entry to 2,2-Disubstituted 2H-Chromenes
NOTICE: This is the peer reviewed version of the following article: Casanova, N., Seoane, A., Mascarelas, J. L., Gulías, M. (2015), Rhodium-Catalyzed (5+1) Annulations Between 2-Alkenylphenols
and Allenes: A Practical Entry to 2,2-Disubstituted 2H-Chromenes. Angew. Chem. Int. Ed., 54: 2374-2377 [doi: 10.1002/anie.201410350]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving.Readily available alkenylphenols react with allenes under rhodium catalysis to provide valuable 2,2-disubstituted 2H-chromenes. The whole process, which involves the cleavage of one C-H bond of the alkenyl moiety and the participation of the allene as a one-carbon cycloaddition partner, can be considered a simple, versatile, and atom-economical (5+1) heteroannulation. The reaction tolerates a broad range of substituents both in the alkenylphenol and in the allene, and most probably proceeds through a mechanism involving a rhodium-catalyzed C-C coupling followed by two sequential pericyclic processes.This work was supported by the Spanish MINECO (grant: SAF2013-41943-R), the ERDF, the European Research Council (Advanced Grant No. 340055), and the Xunta de Galicia (grants: GRC2013-041, EM2013/036 and a Parga Pondal contract to M.G.). We also thank the orfeo-cinqa networkS
Rhodium(III)-Catalyzed Intramolecular Annulations of Acrylic and Benzoic Acids to Alkynes
Rh(III) catalysts can promote a formal (4 + 2) intramolecular oxidative annulation between acrylic or benzoic acid derivatives and alkynes. The reaction, which involves a C–H activation process, allows for a rapid assembly of appealing bicyclic pyran-2-ones and tricyclic isocoumarin derivatives in moderate to good yields. The α-pyrone moiety of the products provides for further manipulations to obtain relatively complex cyclic skeletons in a very simple mannerThis work has received financial support from Spanish grants (SAF2016-76689-R, CTQ2016-77047-P, and FPI fellowship to D.F.F.), the Consellería de Cultura, Educación e Ordenación Universitaria (ED431C 2017/19, 2015-CP082, and Centro Singular de Investigación de Galicia acreditación 2016-2019, ED431G/09), the European Regional Development Fund (ERDF), and the European Research Council (Advanced Grant no. 340055). The orfeo-cinqa network CTQ2016-81797-REDC is also kindly acknowledgedS
Amide-Directed Formation of Five-Coordinate Osmium Alkylidenes from Alkynes
The amide-directed synthesis of five-coordinate osmium alkylidene derivatives from alkynes is reported. These types of complexes, which have been elusive until now because of the tendency of osmium to give hydride alkylidyne species, are prepared by reaction of the dihydride OsH2Cl2(PiPr3)2 (1) with terminal alkynes containing a distal amide group. Complex 1 reacts with N-phenylhex-5-ynamide and N-phenylhepta-6-ynamide to give OsCl2{═C(CH3)(CH2)nNH(CO)Ph}(PiPr3)2 (n = 3 (2), 4 (3)). The relative position of carbonyl and NH groups in the organic substrates has no influence on the reaction. Thus, treatment of 1 with N-(pent-4-yn-1-yl)benzamide leads to OsCl2{═C(CH3)(CH2)3NHC(O)Ph}(PiPr3)2 (4). The new compounds are intermediate species in the cleavage of the C–C triple bond of the alkynes. Under mild conditions, they undergo the rupture of the Cα–CH3 bond of the alkylidene, which comes from the alkyne triple bond, to afford six-coordinate hydride–alkylidyne derivatives. In dichloromethane, complex 2 gives a 10:7 mixture of OsHCl2{≡C(CH2)3C(O)NHPh}(PiPr3)2 (5) and OsHCl2{≡CCH(CH3)(CH2)2C(O)NHPh}(PiPr3)2 (6). The first complex contains a linear separation between the alkylidyne Cα atom and the amide group, whereas the spacer is branched in the second complex. In contrast to the case for 2, complex 4 selectively affords OsHCl2{≡C(CH2)3NHC(O)Ph}(PiPr3)2 (7). In spite of their instability, these compounds give the alkylidene–allene metathesis, being a useful entry to five-coordinate vinylidene complexes, including the dicarbon-disubstituted OsCl2(═C═CMe2)(PiPr3)2 (8) and the monosubstituted OsCl2(═C═CHCy)(PiPr3)2 (9)Financial support from the Spanish MINECO (Projects CTQ2014-52799-P, SAF2013-41943-R, and CTQ2014-51912-REDC), the DGA (E35), the ERDF, the European Research
Council (Advanced Grant No. 340055) and the European Social Fund (FSE), and the Xunta de Galicia (grants GRC2013-041, EM2013/036, 2015-CP082 and a Parga Pondal contract to M.G.) is acknowledge
Palladium(II)-Catalyzed annulation between ortho-alkenylphenols and allenes. Key role of the metal geometry in determining the reaction outcome
2-Alkenylphenols react with allenes, upon treatment with catalytic amounts of Pd(II) and Cu(II), to give benzoxepine products in high yields and with very good regio- and diastereoselectivities. This contrasts with the results obtained with Rh catalysts, which provided chromene-like products through a pathway involving a β-hydrogen elimination step. Computational studies suggest that the square planar geometry of the palladium is critical to favor the reductive elimination process required for the formation of the oxepine productsThis work was supported by the Spanish MINECO (grant:SAF2013-41943-R), the ERDF, the European Research Council (Advanced Grant No. 340055) and the Xunta de
Galicia (grants: GRC2013-041 and 2015-CP082). We also thank the orfeo-cinqa CTQ2014-51912-REDC. K.P.D.R. thanks the Coordenaça̧o de Aperfeiçoamento de Pessoal de ̧Nıvel Superior (CAPES, Brazil) for the Ph.D scholarship. We ́thank Dr. M. Martınez for XRD analysis. All calculations were ́carried out at Centro de Supercomputación de Galicia (CESGA
Rhodium‐Catalyzed Annulation of ortho‐Alkenyl Anilides with Alkynes: Formation of Unexpected Naphthalene Adducts
This is the peer reviewed version of the following article: Seoane, A., Comanescu,C., Casanova, N., García-Fandiño, R., Diz, X., Mascareñas, J.L., Gulías, M. (2019), Rhodium-catalyzed annulation of ortho-alkenylanilides with alkynes: Formation of unexpected naphthalene adducts. AngewChemIntEd., 58,1700-1717 [doi: 10.1002/anie.201811747]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archivingThis research received financial support through Spanish grants SAF2016‐76689‐R and CTQ2016‐77047‐P, from the Consellería de Cultura, Educación e Ordenación Universitaria (ED431C 2017119‐041, 2015‐CP082 and Centro Singular de Investigación de Galicia accreditation 2016‐2019, ED431G/09), the European Regional Development Fund (ERDF), and the European Research Council (Advanced Grant No. 340055). R.G.‐F. thanks the Spanish Government MINECO for a Ramon y Cajal (RYC‐RYC‐2016‐20335) contract. The orfeo‐cinqa network CTQ2016‐81797‐REDC is kindly acknowledged. All calculations were carried out at Centro de Supercomputación de Galicia (CESGA)S
Teriflunomide and Epstein–Barr virus in a Spanish multiple sclerosis cohort: in vivo antiviral activity and clinical response
BackgroundEpstein–Barr virus (EBV) and human herpesvirus 6 (HHV-6) have been associated with multiple sclerosis (MS). Teriflunomide is an oral disease-modifying therapy approved for treatment of relapsing forms of MS. In the preclinical Theiler’s murine encephalitis virus model of MS, the drug demonstrated an increased rate of viral clearance versus the vehicle placebo. Furthermore, teriflunomide inhibits lytic EBV infection in vitro.Objective1. To evaluate the humoral response against EBV and HHV-6 prior to teriflunomide treatment and 6 months later. 2. To correlate the variation in the humoral response against EBV and HHV-6 with the clinical and radiological response after 24 months of treatment with teriflunomide. 3. To analyze the utility of different demographic, clinical, radiological, and environmental data to identify early biomarkers of response to teriflunomide.MethodsA total of 101 MS patients (62 women; mean age: 43.4 years) with one serum prior to teriflunomide onset and another serum sample 6 months later were recruited. A total of 80 had been treated for at least 24 months, 13 had stopped teriflunomide before 24 months, and 8 were currently under teriflunomide therapy but with less than 24 months of follow-up. We analyzed the levels of the viral antibodies titers abovementioned in serum samples with ELISA commercial kits, and the levels of serum neurofilament light chain (Nf-L).ResultsAntiviral antibody titers decreased for EBNA-1 IgG (74.3%), VCA IgG (69%), HHV-6 IgG (60.4%), and HHV-6 IgM (73.3%) after 6 months of teriflunomide. VCA IgG titers at baseline correlated with Nf-L levels measured at the same time (r = 0.221; p = 0.028) and 6 months later (r = 0.240; p = 0.017). We found that higher EBNA-1 titers (p = 0.001) and a higher age (p = 0.04) at baseline were associated with NEDA-3 conditions. Thus, 77.8% of patients with EBNA-1 >23.0 AU and >42.8 years (P50 values) were NEDA-3.ConclusionTreatment with teriflunomide was associated with a reduction of the levels of IgG antibody titers against EBV and HHV-6. Furthermore, higher EBNA-1 IgG titers prior to teriflunomide initiation were associated with a better clinical response
Phagocytosis imprints heterogeneity in tissue-resident macrophages
Tissue-resident macrophages display varying phenotypic and functional properties that are largely specified by their local environment. One of these functions, phagocytosis, mediates the natural disposal of billions of cells, but its mechanisms and consequences within living tissues are poorly defined. Using a parabiosis-based strategy, we identified and isolated macrophages from multiple tissues as they phagocytosed blood-borne cellular material. Phagocytosis was circadianally regulated and mediated by distinct repertoires of receptors, opsonins, and transcription factors in macrophages from each tissue. Although the tissue of residence defined the core signature of macrophages, phagocytosis imprinted a distinct antiinflammatory profile. Phagocytic macrophages expressed CD206, displayed blunted expression of Il1b, and supported tissue homeostasis. Thus, phagocytosis is a source of macrophage heterogeneity that acts together with tissue-derived factors to preserve homeostasis