The Experts below are selected from a list of 477 Experts worldwide ranked by ideXlab platform
Yang Sun - One of the best experts on this subject based on the ideXlab platform.
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andrographolide sulfonate ameliorates lipopolysaccharide induced acute lung injury in mice by down regulating mapk and nf κb pathways
Acta Pharmaceutica Sinica B, 2016Co-Authors: Shuang Peng, Chunhong Jiang, Xiaoling Yang, Wen Liu, Wenjie Guo, Nan Hang, Yang SunAbstract:Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a severe, life-threatening medical condition characterized by widespread inflammation in the lungs, and is a significant source of morbidity and mortality in the patient population. New therapies for the treatment of ALI are desperately needed. In the present study, we examined the effect of andrographolide sulfonate, a water-soluble form of andrographolide (trade name: Xi-Yan-Ping Injection), on lipopolysaccharide (LPS)-induced ALI and inflammation. Andrographolide sulfonate was administered by intraperitoneal injection to mice with LPS-induced ALI. LPS-induced airway inflammatory cell recruitment and lung histological alterations were significantly ameliorated by andrographolide sulfonate. Protein levels of pro-inflammatory cytokines in bronchoalveolar lavage fluid (BALF) and serum were reduced by andrographolide sulfonate administration. mRNA levels of pro-inflammatory cytokines in lung tissue were also suppressed. Moreover, andrographolide sulfonate markedly suppressed the activation of mitogen-activated protein kinase (MAPK) as well as p65 subunit of nuclear factor-κB (NF-κB). In summary, these results suggest that andrographolide sulfonate ameliorated LPS-induced ALI in mice by inhibiting NF-κB and MAPK-mediated inflammatory responses. Our study shows that water-soluble andrographolide sulfonate may represent a new therapeutic approach for treating inflammatory lung disorders.
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andrographolide sulfonate ameliorates experimental colitis in mice by inhibiting th1 th17 response
International Immunopharmacology, 2014Co-Authors: Wen Liu, Xiaoling Yang, Wenjie Guo, Lele Guo, Peifen Cai, Ning Xie, Yongqian Shu, Yang SunAbstract:Abstract Inflammatory bowel disease (IBD) is a chronic, relapsing and remitting condition of inflammation involves overproduction of pro-inflammatory cytokines and excessive functions of inflammatory cells. However, current treatments for IBD may have potential adverse effects including steroid dependence, infections and lymphoma. Therefore new therapies for the treatment of IBD are desperately needed. In the present study, we aimed to examine the effect of andrographolide sulfonate, a water-soluble form of andrographolide (trade name: Xi-Yan-Ping Injection), on murine experimental colitis induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). Andrographolide sulfonate was administrated through intraperitoneal injection to mice with TNBS-induced colitis. TNBS-induced body weight loss, myeloperoxidase activity, shortening of the colon and colonic inflammation were significantly ameliorated by andrographolide sulfonate. Both the mRNA and protein levels of pro-inflammatory cytokines were reduced by andrographolide sulfonate administration. Moreover, andrographolide sulfonate markedly suppressed the activation of p38 mitogen-activated protein kinase as well as p65 subunit of nuclear factor-κB (NF-κB). Furthermore, CD4 + T cell infiltration as well as the differentiation of Th1 (CD4 + IFN-γ + ) and Th17 (CD4 + IL17A + ) subset were inhibited by andrographolide sulfonate. In summary, these results suggest that andrographolide sulfonate ameliorated TNBS-induced colitis in mice through inhibiting Th1/Th17 response. Our study shows that water-soluble andrographolide sulfonate may represent a new therapeutic approach for treating gastrointestinal inflammatory disorders.
Patrick J Walsh - One of the best experts on this subject based on the ideXlab platform.
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Palladium-Catalyzed Arylation of Alkyl Sulfenate Anions
Journal of the American Chemical Society, 2015Co-Authors: Mengnan Zhang, Carol Y. Wang, Hui Jiang, Patrick J WalshAbstract:A unique palladium-catalyzed arylation of alkyl Sulfenate anions is introduced that affords aryl alkyl sulfoxides in high yields. Due to the base sensitivity of the starting sulfoxides, Sulfenate anion intermediates, and alkyl aryl sulfoxide products, the use of a mild method to generate alkyl Sulfenate anions was crucial to the success of this process. Thus, a fluoride triggered elimination strategy was employed with alkyl 2-(trimethylsilyl)ethyl sulfoxides to liberate the requisite alkyl Sulfenate anion intermediates. In the presence of palladium catalysts with bulky monodentate phosphines (SPhos and Cy-CarPhos) and aryl bromides or chlorides, alkyl Sulfenate anions were readily arylated. Moreover, the thermal fragmentation and the base promoted elimination of alkyl sulfoxides was overridden. The alkyl Sulfenate anion arylation exhibited excellent chemoselectivity in the presence of functional groups, such as anilines and phenols, which are also known to undergo palladium catalyzed arylation reactions.
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Palladium-Catalyzed Arylation of Alkyl Sulfenate Anions
2015Co-Authors: Tiezheng Jia, Mengnan Zhang, Carol Y. Wang, Hui Jiang, Patrick J WalshAbstract:A unique palladium-catalyzed arylation of alkyl Sulfenate anions is introduced that affords aryl alkyl sulfoxides in high yields. Due to the base sensitivity of the starting sulfoxides, Sulfenate anion intermediates, and alkyl aryl sulfoxide products, the use of a mild method to generate alkyl Sulfenate anions was crucial to the success of this process. Thus, a fluoride triggered elimination strategy was employed with alkyl 2-(trimethylsilyl)ethyl sulfoxides to liberate the requisite alkyl Sulfenate anion intermediates. In the presence of palladium catalysts with bulky monodentate phosphines (SPhos and Cy-CarPhos) and aryl bromides or chlorides, alkyl Sulfenate anions were readily arylated. Moreover, the thermal fragmentation and the base promoted elimination of alkyl sulfoxides was overridden. The alkyl Sulfenate anion arylation exhibited excellent chemoselectivity in the presence of functional groups, such as anilines and phenols, which are also known to undergo palladium catalyzed arylation reactions
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a new class of organocatalysts Sulfenate anions
Angewandte Chemie, 2014Co-Authors: Mengnan Zhang, Tiezheng Jia, Haolin Yin, Patrick J Carroll, Eric J Schelter, Patrick J WalshAbstract:Sulfenate anions are known to act as highly reactive species in the organic arena. Now they premiere as organocatalysts. Proof of concept is offered by the sulfoxide/Sulfenate-catalyzed (1–10 mol %) coupling of benzyl halides in the presence of base to generate trans-stilbenes in good to excellent yields (up to 99 %). Mechanistic studies support the intermediacy of Sulfenate anions, and the deprotonated sulfoxide was determined to be the resting state of the catalyst.
Manolis Stratakis - One of the best experts on this subject based on the ideXlab platform.
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regiocontrolled synthesis of γ hydroxybutenolides via singlet oxygen mediated oxidation of 2 thiophenyl furans
Journal of Organic Chemistry, 2016Co-Authors: Vasiliki Kotzabasaki, Georgios Vassilikogiannakis, Manolis StratakisAbstract:Photooxygenation of 2-thiophenyl-substituted furans in ethanol leads to the rapid, regiocontrolled, and quantitative synthesis of γ-hydroxybutenolides. The carbonyl group in butenolide holds the position of thiophenyl moiety in reacting furans. Decomposition of the initially formed [4 + 2] endoperoxide into products through a radical chain mechanism is proposed, as the fate of thiophenyl moiety is its transformation into ethyl phenylSulfenate (PhS-OEt) and diphenyldisulfide. Under the reaction conditions, the Sulfenate is fast oxidized into the corresponding sulfinate.
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Regiocontrolled Synthesis of γ‑Hydroxybutenolides via Singlet Oxygen-Mediated Oxidation of 2‑Thiophenyl Furans
2016Co-Authors: Vasiliki Kotzabasaki, Georgios Vassilikogiannakis, Manolis StratakisAbstract:Photooxygenation of 2-thiophenyl-substituted furans in ethanol leads to the rapid, regiocontrolled, and quantitative synthesis of γ-hydroxybutenolides. The carbonyl group in butenolide holds the position of thiophenyl moiety in reacting furans. Decomposition of the initially formed [4 + 2] endoperoxide into products through a radical chain mechanism is proposed, as the fate of thiophenyl moiety is its transformation into ethyl phenylSulfenate (PhS-OEt) and diphenyldisulfide. Under the reaction conditions, the Sulfenate is fast oxidized into the corresponding sulfinate
Sherine N Khattab - One of the best experts on this subject based on the ideXlab platform.
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Sulfonate Esters of 1‐Hydroxypyridin‐2(1H)‐one and Ethyl 2‐Cyano‐2‐(hydroxyimino)acetate (Oxyma) as Effective Peptide Coupling Reagents to Replace 1‐Hydroxybenzotriazole and 1‐Hydroxy‐7‐azabenzotriazole.
ChemInform, 2010Co-Authors: Sherine N KhattabAbstract:The title oxyma sulfonate esters, NOXY and TOXY are more efficient alternatives to the benzotriazole sulfonate esters in terms of racemization suppression and coupling effectiveness.
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Sulfonate Esters of 1-Hydroxypyridin-2(1H)-one and Ethyl 2-Cyano-2- (hydroxyimino)acetate (Oxyma) as Effective Peptide Coupling Reagents to Replace 1-Hydroxybenzotriazole and 1-Hydroxy-7-azabenzotriazole
Chemical & Pharmaceutical Bulletin, 2010Co-Authors: Sherine N KhattabAbstract:A new family of sulfonate ester-type coupling reagents is described which differs in its leaving group. The sulfonate ester coupling reagents ethyl 2-cyano-2-(naphthalen-2-ylsulfonyloxyimino)acetate (NpsOXY), and ethyl 2-cyano-2-(tosyloxyimino)acetate (TsOXY) are more efficient alternatives to the benzotriazole sulfonate esters in terms of racemization suppression and coupling effectiveness. Both oxyma and its related sulfonate esters can be handled with a considerably lower risk than the explosive benzotriazole and its derivatives. 2-Oxopyridin-1(2H)yl naphthalene-2-sulfonate (NpsOPy) and 2-oxopyridin-1(2H)-yl 4-methylbenzenesulfonate (TsOPy) sulfonate esters derived from 1-hydroxypyridin-2(1H)-one were also successfully used as new coupling reagents requiring a longer preactivation time during the coupling process. An improvement in yield and almost comparable optical purity to that of the 1-hydroxy-benzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) analogues was observed.
Michael C Willis - One of the best experts on this subject based on the ideXlab platform.
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Copper-Catalyzed Synthesis of Activated Sulfonate Esters from Boronic Acids, DABSO, and Pentafluorophenol
Organic Letters, 2018Co-Authors: Vincent Vedovato, Eric P. A. Talbot, Michael C WillisAbstract:The synthesis of pentafluorophenyl (PFP) sulfonate esters based on the Pd-catalyzed sulfination of aryl and heteroaryl boronic acids is reported. The sulfinate intermediates are converted in situ to the corresponding sulfonate esters using a copper-catalyzed oxidative process, providing a broad range of PFP esters in good yields.
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Copper-Catalyzed Synthesis of Activated Sulfonate Esters from Boronic Acids, DABSO, and Pentafluorophenol
2018Co-Authors: Vincent Vedovato, Eric P. A. Talbot, Michael C WillisAbstract:The synthesis of pentafluorophenyl (PFP) sulfonate esters based on the Pd-catalyzed sulfination of aryl and heteroaryl boronic acids is reported. The sulfinate intermediates are converted in situ to the corresponding sulfonate esters using a copper-catalyzed oxidative process, providing a broad range of PFP esters in good yields
