Gotowe bibliografie tematyczne / Sulfoximine Directed C-H Activation

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Gotowa bibliografia na temat „Sulfoximine Directed C-H Activation”

Autor: Grafiati

Data publikacji: 6 września 2023

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Artykuły w czasopismach na temat "Sulfoximine Directed C-H Activation"

Li, Yang, i Lin Dong. "Rhodium-catalyzed benzoisothiazole synthesis by tandem annulation reactions of sulfoximines and activated olefins". Organic & Biomolecular Chemistry 15, nr 47 (2017): 9983–86. http://dx.doi.org/10.1039/c7ob02586f.

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Yadav, M. Ramu, Raja K. Rit i Akhila K. Sahoo. "Sulfoximine Directed Intermolecular o-C–H Amidation of Arenes with Sulfonyl Azides". Organic Letters 15, nr 7 (11.03.2013): 1638–41. http://dx.doi.org/10.1021/ol400411v.

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Gabriele, Bartolo. "ChemInform Abstract: Geometrically Directed C-H Activation". ChemInform 44, nr 43 (7.10.2013): no. http://dx.doi.org/10.1002/chin.201343224.

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Yadav, M. Ramu, Raja K. Rit i Akhila K. Sahoo. "ChemInform Abstract: Sulfoximine Directed Intermolecular o-C-H Amidation of Arenes with Sulfonyl Azides." ChemInform 44, nr 31 (11.07.2013): no. http://dx.doi.org/10.1002/chin.201331076.

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Sunnam, Sunil Kumar, i Jitendra D. Belani. "Aryne Multicomponent Reactions by Directed C−H Activation". Chemistry – A European Journal 27, nr 34 (26.05.2021): 8846–50. http://dx.doi.org/10.1002/chem.202100205.

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Tóth, Balázs L., Anna Monory, Orsolya Egyed, Attila Domján, Attila Bényei, Bálint Szathury, Zoltán Novák i András Stirling. "The ortho effect in directed C–H activation". Chemical Science 12, nr 14 (2021): 5152–63. http://dx.doi.org/10.1039/d1sc00642h.

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The term and concept of Ortho Effect (OE) is introduced for the description of steric effects in transition metal catalyzed directed ortho C–H activation reactions to explain and predict reactivities of substrates.

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Sun, Qiao, i Naohiko Yoshikai. "Cobalt-catalyzed C(sp2)–H/C(sp3)–H coupling via directed C–H activation and 1,5-hydrogen atom transfer". Organic Chemistry Frontiers 5, nr 4 (2018): 582–85. http://dx.doi.org/10.1039/c7qo00906b.

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Liu, Yunyun, i Baoli Zhao. "Step-Economical C–H Activation Reactions Directed by In Situ Amidation". Synthesis 52, nr 21 (18.05.2020): 3211–18. http://dx.doi.org/10.1055/s-0040-1707124.

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Owing to the inherent ability of amides to chelate transition-metal catalysts, amide-directed C–H activation reactions constitute a major tactic in directed C–H activation reactions. While the conventional procedures for these reactions usually involve prior preparation and purification of amide substrates before the C–H activation, the step economy is actually undermined by the operation of installing the directing group (DG) and related substrate purification. In this context, directed C–H activation via in situ amidation of the crude material provides a new protocol that can significantly enhance the step economy of amide-directed C–H activation. In this short review, the advances in C–H bond activation reactions mediated or initiated by in situ amidation are summarized and analyzed.1 Introduction2 In Situ Amidation in Aryl C–H Bond Activation3 In Situ Amidation in Alkyl C–H Bond Activation4 Annulation Reactions via Amidation-Mediated C–H Activation5 Remote C–H Activation Mediated by Amidation6 Conclusion

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Kondalarao, Koneti, Somratan Sau i Akhila K. Sahoo. "Sulfoximine Assisted C–H Activation and Annulation via Vinylene Transfer: Access to Unsubstituted Benzothiazines". Molecules 28, nr 13 (27.06.2023): 5014. http://dx.doi.org/10.3390/molecules28135014.

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In this study, we report the synthesis of unsubstituted 1,2-benzothiazines through a redox-neutral Rh(III)-catalyzed C–H activation and [4+2]-annulation of S–aryl sulfoximines with vinylene carbonate. Notably, the introduction of an N-protected amino acid ligand significantly enhances the reaction rate. The key aspect of this redox-neutral process is the utilization of vinylene carbonate as an oxidizing acetylene surrogate and an efficient vinylene transfer agent. This vinylene carbonate enables the cyclization with the sulfoximine motifs, successfully forming a diverse array of 1,2-benzothiazine derivatives in moderate to good yields. Importantly, this study highlights the potential of Rh(III)-catalyzed C–H activation and [4+2]-annulation reactions for the synthesis of optically pure 1,2-benzothiazines with high enantiomeric purity.

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Jun, C. H., i J. H. Lee. "Application of C-H and C-C bond activation in organic synthesis". Pure and Applied Chemistry 76, nr 3 (1.01.2004): 577–87. http://dx.doi.org/10.1351/pac200476030577.

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Rozprawy doktorskie na temat "Sulfoximine Directed C-H Activation"

Guo, Xiangyu. "Ruthenium-catalyzed C-C bond formation via functional-group directed C-H bond activation". Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110570.

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AbstractRuthenium-Catalyzed C-C Bond Formation via Functional-Group Directed C-H Bond ActivationXiangyu GuoAdvisor: Prof. Chao-Jun LiMcGill UniversityThis thesis is an investigation on the formation of carbon-carbon (C-C) bonds in the presence of ruthenium catalyst.In the first part of this thesis, oxidative dehydrogenative coupling reactions for carbon-carbon (C-C) bond formation are described. A ruthenium-catalyzed dimerization of 2-phenylpyridine derivatives is demonstrated to synthesize biaryls using iron(III) chloride as the terminal oxidant. In addition, the oxidative cross coupling of arenes and cycloalkanes is also illustrated, achieving a unique para-selectivity.In the second part of the thesis, a ruthenium-catalyzed olefination via decarbonylative addition of aldehydes to terminal alkynes is described. Conjugated and isolated C=C bonds can be chemoselectively generated in two catalytic systems starting from aromatic and aliphatic aldehydes. The method provides an alternative synthesis of C=C bonds from direct C-H bond addition to triple bonds.
RésuméRuthenium-Catalyzed C-C Bond Formation via Functional-Group Directed C-H Bond ActivationXiangyu GuoSuperviseur: Prof. Chao-Jun LiUniversité McGillCette thèse est le résultat de la recherche sur la formation de liaisons carbone-carbone (C-C), catalysé par le ruthénium. La première partie de cette thèse expose les résultats sur la formation de liaison carbone-carbone (C-C) par la réaction de couplage oxydant par déshydrogénation. La synthèse de composés biaryl par l'utilisation d'un catalyseur de ruthénium a permis la dimérisation des dérivés de la 2-phénylpyridine en présence de chlorure de fer (III) comme oxydant terminal. En outre, l'oxydative cross-coupling entre arènes et cycloalcanes, a montrer une notable, para-sélectivité. La seconde partie de cette thèse, décrit les résultats obtenue sur la réaction d'oléfination decarbonylative entre un aldéhyde et un alcyne vrai, catalyser par le ruthénium. En partant d'aldéhydes aromatiques ou aliphatiques et par l'utilisation de deux systèmes catalytiques, la synthèse chemioselective de double liaison C=C conjuguée ou isolée ont pu être réalisé. Cette réaction fournit ainsi, une intéressante alternative à la synthèse de doubles liaisons C=C par la directe addition de liaison C-H sur une triple liaison.

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Wan, Yung-Chih, i 萬勇志. "Pd-catalyzed synthesis of fluorenones via nitrile directed C-H bond activation". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/68362267711970399165.

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碩士
淡江大學
化學學系碩士班
101
We are successfully in developing a composite system of [Pd]/[Ag]/TFA to catalyze cascade reactions of nitrile directed remote C–H bond activation with insertion of nitrile (part 1), meanwhile, as we change the starting materials from Biphenyl-2-carbonitriles to Benzonitriles and Iodobenzenes (part 2) , the desired products could also be obtained by changing the species of the silver ions donor and it’s stoichiometric amount, through the using of this composite system, variously poly-substituted fluorenones were afforded in moderate to good yields with tolerance of a wide variety of substrates. In third part, 2''-Bromo-[1,1''-biphenyl]-2-carbonitriles were as starting materials which were reacted with Grignard reagent and catalyzed by copper to synthesize phenanthridines in one-pot, further studies to explore the tolerance of the different substrates are currently underway.

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ZHAO, YIGANG. "Reduction of Tertiary Benzamides to Benzaldehydes by an in situ-Generated Schwartz Reagent (Cp2Zr(H)Cl); Formal Synthesis of Lysergic Acid 2. Ru-Catalyzed Amide-Directed Aryl C-H, C-N and C-O Bond Functionalizations: C-B Formation, C-C Suzuki Cross Coupling and Hydrodemethoxylation". Thesis, 2010. http://hdl.handle.net/1974/6671.

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Chapter 2 of the thesis describes a highly efficient in situ method for the reduction of amides to aldehydes and aryl O-carbamates to phenols and other transformations involving hydrozirconations. The method, as a three-component-type reaction, involves in situ generation of the Schwartz reagent (Cp2Zr(H)Cl) from Cp2ZrCl2 and the reductant, LiAlH(O-t-Bu)3, and immediate reaction with a substrate. Substrates include aliphatic and aromatic tertiary amides which are reduced to aldehydes, aryl O-carbamates which are reduced to phenols, and alkynes which undergo other transformations via hydrozirconation. Compared to prior methods, this method has advantage in that reagents are inexpensive and stable, reaction times are short, and reaction temperatures are generally conveniently at room temperature. The use of the in situ method described herein instead of the requirement for the synthesis of the commercially available Schwartz reagent is estimated to provide more than 50% reduction in cost. Chapter 3 of the thesis describes the discovery and development of efficient and regioselective Ru-catalyzed amide-directed C-H, C-N, C-O activation/C-C bond forming reactions, ester-directed C-O activation/C-C bond forming reaction, and amide-directed C-O activation/hydrodemethoxylation reactions under a simple RuH2(CO)(PPh3)3/toluene catalytic system. Of these, the amide-directed C-H activation/cross coupling reaction proceeds well but uniquely on furan 3-amide substrates while the ester-directed C-O activation is effective on the 2-MeO-1-naphthoic acid methyl ester. On the other hand, the amide-directed C-N and C-O activation/coupling reactions are broadly applicable on benzamides and naphthamides. All of these achievements of directed C-H, C-N, C-O activation/coupling reactions complement and may supercede the DoM (directed ortho metalation)-cross coupling strategy, and establish the catalytic base-free DoM-cross coupling process at non-cryogenic temperature as a convenient, economical and green alternative. The new catalytic amide-directed ortho-hydrodemethoxylation reaction has potential value in links to aromatic electrophilic substitution and DoM chemistries. Furthermore, a new borylation reaction via Ru-catalyzed amide-directed C-H activation/C-B bond forming process is also reported herein.
Thesis (Ph.D, Chemistry) -- Queen's University, 2010-12-21 11:12:35.564

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Chen, Yu-Wen, i 陳俞汶. "Part I: Aryl Coupling Directed by C-H Activation Using Organocatalyst;Part II: Tuning Bis-Quinoline-Oligopyrrole Amide Conjugate". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/88122480235096968292.

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碩士
國立中山大學
化學系研究所
101
Part I: The substructure of biaryl is an important motif in many pharmaceutically relevant and biologically active compounds. As a result, for over a century, organic chemists have sought to develop new and more efficient aryl-aryl bond forming methods. However, using of transition metals to synthetic drugs is limited by residuals of metal impurities and the financial cost of the metal catalyst. Therefore the purpose of our experiment is to find an organocatalytic method for constructing biaryls through aromatic C-H activation. Synthetic phenanthroline derivatives were treated as organocatalyst for different aromatic and heterocyclic ring coupling reactions. Part II: Inhibition of telomerase activity through inducing or stabilization of G-quadruplex DNA structures of human telomere was capable to achieve the anti-cancer effect. The first improvement is the synthesis of Bis-quinoline in the past laboratory ways to reduce the number of steps. Synthetic Bis-quinoline oligopyrrole compounds were found to interact with G-quadruplex DNA slightly and they were assumed to be limited by the rigid structure. In this study, we are attempting to introduce glycine as the connection bridge between bis-quinoline and oligopyrrole. Therefore the softer structures are expecting to better fit into the G-quadruplex DNA secondary structure.

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Części książek na temat "Sulfoximine Directed C-H Activation"

Shang, Rui. "Recent Developments of Iron-Catalyzed Directed C–H Activation/C–C Bond Formation Reactions". W Springer Theses, 161–74. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-3193-9_9.

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Davies, H. M. L., i D. Morton. "Heteroatom-Directed C—H Functionalization". W Stereoselective Pericyclic Reactions, Cross Coupling, and C—H and C—X Activation, 1. Georg Thieme Verlag KG, 2011. http://dx.doi.org/10.1055/sos-sd-203-00354.

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Davies, H. M. L., i D. Morton. "Directed sp C—H Bond Insertion". W Stereoselective Pericyclic Reactions, Cross Coupling, and C—H and C—X Activation, 1. Georg Thieme Verlag KG, 2011. http://dx.doi.org/10.1055/sos-sd-203-00337.

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Chatani, N. "1.14 Nickel-Catalyzed Directed C—H Functionalization". W Base-Metal Catalysis 1. Stuttgart: Georg Thieme Verlag KG, 2023. http://dx.doi.org/10.1055/sos-sd-238-00266.

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AbstractThis chapter summarizes some selected examples of nickel-catalyzed directed C—H functionalization reactions that involve the activation of a C—H bond as a key step. It is now recognized that nickel complexes, mostly nickel(0) and nickel(II), are some of the most attractive and effective catalysts for the development of C—H functionalization reactions because of the low cost and earth-abundance of nickel, and, most importantly, because the complexes can exist in various oxidation states (+1, +2, +3, and +4) during the transformation, which leads to unique reactivity.

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Thrimurtulu, Neetipalli, Aniruddha Dey, Debabrata Maiti i Chandra M. R. Volla. "Recent Developments in Palladium-Catalyzed Natural Product Synthesis via C H Activation". W Strategies for Palladium-Catalyzed Non-Directed and Directed C-H Bond Functionalization, 453–70. Elsevier, 2017. http://dx.doi.org/10.1016/b978-0-12-805254-9.00012-8.

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Banerjee, S., i L. Ilies. "2.8 Iron-Catalyzed C—H Functionalization". W Base-Metal Catalysis 2. Stuttgart: Georg Thieme Verlag KG, 2023. http://dx.doi.org/10.1055/sos-sd-239-00143.

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AbstractThe direct functionalization of an organic substrate via transition-metal-catalyzed C—H bond activation is a powerful tool for building molecular complexity. Despite the abundance, low cost, and low toxicity of iron, which make it an ideal metal for sustainable catalysis, iron-catalyzed C—H activation has been less investigated compared with catalysis based on precious metals such as palladium or iridium. In this chapter, selected examples of iron-catalyzed activation of a C—H bond to create a new C—C bond are described. Arylation, hetarylation, alkenylation, and alkylation of C(sp2)—H and C(sp3)—H bonds is discussed. Most of the substrates require a directing group, but several examples of non-directed reactions are also presented. The functionalization of a C—H bond has been achieved by using organometallic reagents, organic halides and pseudohalides, multiple bonds such as alkenes and alkynes, and arenes or hetarenes as the reaction partner.

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Taber, Douglass F. "C-H Functionalization: The Chen Synthesis of Celogentin C". W Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0019.

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Christian R. Goldsmith of Auburn University developed (Synlett 2010, 1377) a method for radical chlorination of 1 using commercial peracetic acid. Noritaka Mizuno of the University of Tokyo devised (Nat. Chem. 2010, 2, 478) a bulky polyoxometalate that mediated the selective hydroxylation of the secondary C-H bonds of 3. Christina White of the University of Illinois showed (Science 2010, 327, 566) that Fe-mediated C-H oxidation is sensitive to the expected electronic effects, so that 5 was selectively oxidized to 6. Irena S. Akhrem of the A. N. Nesmeyanov Institute of Organoelement Compounds established (Tetrahedron Lett. 2010, 51, 259) that a C-H bond of 7 could be efficiently converted to a C-C bond. Melanie S. Sanford of the University of Michigan extended (Organic Lett. 2010, 12, 532) directed palladation to 9, effecting selective acetoxylation of the methyl group. Herman O. Sintim of the University of Maryland observed (Angew. Chem. Int. Ed. 2010, 49, 3964) that the O-linked diazoamide 11 selectively cyclized to 12. The corresponding C-linked diazoamide gave only five-membered ring formation. Yasushi Obora and Yasutaka Ishii of Kansai University devised (Organic Lett. 2010, 12, 1372) conditions for the selective allylic amination of 13. Marvin J. Miller of the University of Notre Dame developed (Tetrahedron Lett. 2010, 51, 328) the nitrosoisoxazole 16 for the allylic amination of 15. David A. Powell of Merck Frosst established (J. Org. Chem. 2010, 75, 2726) a protocol for the selective amination of the aromatic methyl group of 18. Ying-Yeung Yeung of the National University of Singapore effected (Organic Lett. 2010, 12, 2128) selective allylic oxidation of 21 with a hypervalent iodine reagent. Gullapalli Kumaraswamy of the Indian Institute of Chemical Technology, Hyderabad, allylated (J. Org. Chem. 2010, 75, 3916) an amine 23 using commercial aqueous t -BuOOH. Corey R. J. Stephenson of Boston University used (J. Am. Chem. Soc. 2010, 132, 1464) visible light to activate 26 for homologation to 27. In the course of a synthesis of the bicyclic nonribosomal peptide celogentin C, isolated from the seeds of the plumed cockscomb Celosia argentea, Gong Chen of Pennsylvania State University took advantage (Angew. Chem. Int. Ed. 2010, 49, 958) of Pd activation to effect specific coupling of the iodoindole 29 with the leucine derivative 28. On a 4-gram scale, this coupling proceeded in 85% yield.

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K. Patel, Bhisma, i Amitava Rakshit. "Access to N-Heterocyclic Molecules via Ru(II)-Catalyzed Oxidative Alkyne Annulation Reactions". W Ruthenium - an Element Loved by Researchers [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95987.

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In last few decades, the transition metal-catalyzed C-H bond activation and alkyne annulation reactions have turned out to be effective methods for the construction of highly important heterocycles. In particular, the Ru(II) catalysts have been used for the oxidative coupling between an internal alkynes and readily available nitrogen directed compounds in a rapid and sustainable manner. The Ru(II) catalysts are very much beneficial due to their stability in both air and water, ease of preparation, inexpensive than those of Rh(III) and designer Co(III) catalysts usually used for alkyne annulation reactions, requirement of mild reaction conditions, and compatible with various oxidants. Owing to these advantages of Ru(II) catalysts herein, we attempt to highlight the recent development in C-H activation and annulation reactions, which lead to the formation of several important N-heterocycles.

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Streszczenia konferencji na temat "Sulfoximine Directed C-H Activation"

Meusburger, S., R. Beckmann, J. Wojta i B. R. Binder. "RELATION OP FIBRIN STIMULATION OF tPA MEDIATED PLASMINOGEN ACTIVATION AND FIBRIN BINDING TOWARDS FIBRONEKTIN AS REVEALED BY A MONOCLONAL ANTIBODY (MAB) AGAINST FCB-2 FIBRINOGEN FRAGMENTS". W XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644403.

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Fibrin binds to the finger domain of fibronektin via the C-terminal end of the chain and it was reported previously by us that in a fluid phase assay fibronektin inhibits fibrin enhancement of plasminogen activation by tPA. However, other have shown that tPA binds to fibronectin thereby possibly mediating enhanced matrix bound plasmin formation. In the present study we tried to further characterize the interaction between fibronectin and fibrin in regard to fibrin dependent enhancement of plasminogen activation by tPA. For fibrin binding to fibronectin we have developed an ELISA system using fibronectin coated plates and antibodies against fibrin(ogen) to quantify bound fibrin. For determination of plasminogen activation we used a coupled spectrophotometric fluid phase assay with Glu-plasminogen as substrate and H-D-Val-Leu-Lys-pNA to quantify the formed plasmin. Fibrin binding to coated fibronectin was linear between 500ng and 1 mg/ml for fibrin monomers (reptilase), FCB-2 fragments and thrombin (3.3 U/ml) treated fibrinogen, respectively. A monoclonal antibody directed against the FCB-2 fibrinogen fragment which also could be shown to recognize fibirn but not fibrinogen did not recognize fibronectin bound fibrin and inhibited also the fibrin stimulatory effect on plasminogen activation indicating that the epitope against which the antibody is directed is closely related to both the fibronectin binding site and the site involved in t-PA stimulation.

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Gimbrone, M. A., M. P. Bevilacqua i M. E. Wheeler. "ENDOTHELIAL-DEPENDENT MECHANISMS OF LEUKOCYTE ADHESION: ROLE OF MONOKINES". W XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643983.

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Localized adhesion of peripheral blood leukocytes to the vessel wall is an essential component of inflammatory reactions. There is increasing experimental evidence that vascular endothelial cells play an active role in this process. Our laboratory has been especially interested in defining endothelial-dependent mechanisms of leukocyte adhesion, and the role of leukocyte products in their modulation. We have reported1 that purified natural human monocyte-derived interleukin 1 (IL-1) can act directly on cultured human endothelial cells (HEC) to dramatically increase the adhesiveness of their surfaces for human polymorphonuclear leukocytes (PMN), monocytes and the related cell lines HL-60 and U937. This effect was concentration-, time- (onset≅30 min; peak≅4h) , and protein/RNA-synthesis-requiring, and, in selective pretreatment/fixation experiments, was shown to be mediated primarily through the endothelial cell. To better define this inducible endothelial pro-adhesive mechanism, we have developed a series of murine monoclonal antibodies directed against monokine-stimulated HEC surfaces. One of these antibodies (H4/18) recognizes an endothelial cell surface structure which is induced by IL-1 (and certain other cytokines)2 in a similar fashion (kinetics, concentration - dependence, sensitivity to metabolic inhibitors) as the pro-adhesive surface change for leukocytes. H4/18 partially blocks HD-60 cell adhesion to monokine-treated HEC, and, in vivo, labels human vascular endothelium at sites of experimental delayed hypersensitivity reactions4. A second monoclonal antibody (H18/7)5 significantly blocks the adhesion of both HL-60 cells and PMN to monokine-treated HEC. Monoclonal antibodies H4/18 and H18/7 appear to recognize the same inducible surface structure as assessed by immunoprecipitation of extracts of metabolically labeled, monokine-stimulated HEC. We have designated this monokine-inducible, endothelial-leukocyte adhesion molecule "E-IAM 1". IL-1 treated HEC cultures (in contrast to sham-treated control cultures) generate a soluble leukocyte adhesion inhibitor (LAI)6,7. LAI acts on PMN to inhibit their adhesion to hyperadhesive endothelial monolayers as well as to serum-coated plastic surfaces, but does not inhibit PMN activation by chemotactic stimuli (LTB4, f-met-leu-phe). IAI appears to differentially inhibit adhesion of peripheral blood leukocytes, isolated from the same donor, to hyperadhesive HEC (PMN > monocytes; lymphocytes, no effect), and does not inhibit HL-60 cell-HEC adhesion. Endothelial production of IAI is time-dependent (peak 5-6 h.), and blocked by cycloheximide but not by aspirin. Preliminary characterization indicates that LAI is nonsedimentable (250,000 xg, 45 min), nondialyzable (>10 kD), stable to heat (80°C, 30 min) and acid (pH 2) and is precipitable by ammonium sulphate (60-80% saturation). Thus, this endothelial-derived inhibitory activity, which appears to be distinct from PGI2 or other cyclooxygenase products, blocks leukocyte adhesion without globally suppressing leukocyte function. Further characterization of the cellular and molecular mechanisms regulating the endothelial expression of E-LAM 1 and LAI should contribute to our understanding of the active role of the vascular wall in the inflammatory process.1. Bevilacqua et al. (1985); J. Clin. Invest.76:2003.2. Cotran et al. (1986); J. Exp. Med. 164:661.3. Bevilacqua et al. (1987); Fed. Proc. (in press).4. Wheeler et al. (1986); Fed. Proc. 45:1725.5. Wheeler et al. (1987); Fed. Proc. (in press).

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Raporty organizacyjne na temat "Sulfoximine Directed C-H Activation"

Rafaeli, Ada, i Russell Jurenka. Molecular Characterization of PBAN G-protein Coupled Receptors in Moth Pest Species: Design of Antagonists. United States Department of Agriculture, grudzień 2012. http://dx.doi.org/10.32747/2012.7593390.bard.

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The proposed research was directed at determining the activation/binding domains and gene regulation of the PBAN-R’s thereby providing information for the design and screening of potential PBAN-R-blockers and to indicate possible ways of preventing the process from proceeding to its completion. Our specific aims included: (1) The identification of the PBAN-R binding domain by a combination of: (a) in silico modeling studies for identifying specific amino-acid side chains that are likely to be involved in binding PBAN with the receptor and; (b) bioassays to verify the modeling studies using mutant receptors, cell lines and pheromone glands (at tissue and organism levels) against selected, designed compounds to confirm if compounds are agonists or antagonists. (2) The elucidation ofthemolecular regulationmechanisms of PBAN-R by:(a) age-dependence of gene expression; (b) the effect of hormones and; (c) PBAN-R characterization in male hair-pencil complexes. Background to the topic Insects have several closely related G protein-coupled receptors (GPCRs) belonging to the pyrokinin/PBAN family, one with the ligand pheromone biosynthesis activating neuropeptide or pyrokinin-2 and another with diapause hormone or pyrokinin-1 as a ligand. We were unable to identify the diapause hormone receptor from Helicoverpa zea despite considerable effort. A third, related receptor is activated by a product of the capa gene, periviscerokinins. The pyrokinin/PBAN family of GPCRs and their ligands has been identified in various insects, such as Drosophila, several moth species, mosquitoes, Triboliumcastaneum, Apis mellifera, Nasoniavitripennis, and Acyrthosiphon pisum. Physiological functions of pyrokinin peptides include muscle contraction, whereas PBAN regulates pheromone production in moths plus other functions indicating the pleiotropic nature of these ligands. Based on the alignment of annotated genomic sequences, the primary and secondary structures of the pyrokinin/PBAN family of receptors have similarity with the corresponding structures of the capa or periviscerokinin receptors of insects and the neuromedin U receptors found in vertebrates. Major conclusions, solutions, achievements Evolutionary trace analysisof receptor extracellular domains exhibited several class-specific amino acid residues, which could indicate putative domains for activation of these receptors by ligand recognition and binding. Through site-directed point mutations, the 3rd extracellular domain of PBAN-R was shown to be critical for ligand selection. We identified three receptors that belong to the PBAN family of GPCRs and a partial sequence for the periviscerokinin receptor from the European corn borer, Ostrinianubilalis. Functional expression studies confirmed that only the C-variant of the PBAN-R is active. We identified a non-peptide agonist that will activate the PBAN-receptor from H. zea. We determined that there is transcriptional control of the PBAN-R in two moth species during the development of the pupa to adult, and we demonstrated that this transcriptional regulation is independent of juvenile hormone biosynthesis. This transcriptional control also occurs in male hair-pencil gland complexes of both moth species indicating a regulatory role for PBAN in males. Ultimate confirmation for PBAN's function in the male tissue was revealed through knockdown of the PBAN-R using RNAi-mediated gene-silencing. Implications, both scientific and agricultural The identification of a non-peptide agonist can be exploited in the future for the design of additional compounds that will activate the receptor and to elucidate the binding properties of this receptor. The increase in expression levels of the PBAN-R transcript was delineated to occur at a critical period of 5 hours post-eclosion and its regulation can now be studied. The mysterious role of PBAN in the males was elucidated by using a combination of physiological, biochemical and molecular genetics techniques.

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