共查询到20条相似文献,搜索用时 15 毫秒
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Shi Xu Akil Hamsath Deshka L. Neill Yingying Wang Dr. Chun-tao Yang Prof. Dr. Ming Xian 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4005-4016
Reactive sulfur species (RSS) play regulatory roles in biological systems. Many RSS are highly reactive and transient molecules, making their study difficult. RSS donors or precursors, which are used to specifically produce or deliver RSS, are useful research tools, as well as possible therapeutic agents. In this Minireview, we summarized the chemical strategies that have been used in the design of donors/precursors of hydrogen sulfide relevant RSS (including hydrogen sulfide, hydrogen polysulfides, persulfides, and S-nitroso-hydrogen sulfide). The potential problems of applying these strategies in biological settings are also discussed. 相似文献
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Chao Liu Dr. Cangjie Yang Seung Hwang Samantha L. Ferraro James P. Flynn Prof. Dr. Jia Niu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18593-18599
O-sulfation is an important chemical code widely existing in bioactive molecules, but the scalable and facile synthesis of complex bioactive molecules carrying O-sulfates remains challenging. Reported here is a general approach to O-sulfation by the sulfur(VI) fluoride exchange (SuFEx) reaction between aryl fluorosulfates and silylated hydroxy groups. Efficient sulfate diester formation was achieved through systematic optimization of the electronic properties of aryl fluorosulfates. The versatility of this O-sulfation strategy was demonstrated in the scalable syntheses of a variety of complex molecules carrying sulfate diesters at various positions, including monosaccharides, disaccharides, an amino acid, and a steroid. Selective hydrolytic and hydrogenolytic removal of the aryl masking groups from sulfate diesters yielded the corresponding O-sulfate products in excellent yields. This strategy provides a powerful tool for the synthesis of O-sulfate bioactive compounds. 相似文献
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An N‐Acetyl Cysteine Ruthenium Tricarbonyl Conjugate Enables Simultaneous Release of CO and Ablation of Reactive Oxygen Species 下载免费PDF全文
Dr. João D. Seixas Dr. Miguel Chaves‐Ferreira Diana Montes‐Grajales Ana M. Gonçalves Dr. Ana R. Marques Dr. Lígia M. Saraiva Prof. Jesus Olivero‐Verbel Prof. Carlos C. Romão Dr. Gonçalo J. L. Bernardes 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(42):14708-14712
We have designed and synthesised a [Ru(CO)3Cl2(NAC)] pro‐drug that features an N‐acetyl cysteine (NAC) ligand. This NAC carbon monoxide releasing molecule (CORM) conjugate is able to simultaneously release biologically active CO and to ablate the concurrent formation of reactive oxygen species (ROS). Complexes of the general formulae [Ru(CO)3(L)3]2+, including [Ru(CO)3Cl(glycinate)] (CORM‐3), have been shown to produce ROS through a water–gas shift reaction, which contributes significantly, for example, to their antibacterial activity. In contrast, NAC‐CORM conjugates do not produce ROS or possess antibacterial activity. In addition, we demonstrate the synergistic effect of CO and NAC both for the inhibition of nitric oxide (formation) and in the expression of tumour‐necrosis factor (TNF)‐α. This work highlights the advantages of combining a CO‐releasing scaffold with the anti‐oxidant and anti‐inflammatory drug NAC in a unique pro‐drug. 相似文献
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Interrupted Pummerer Reaction in Latent‐Active Glycosylation: Glycosyl Donors with a Recyclable and Regenerative Leaving Group 下载免费PDF全文
Penghua Shu Xiong Xiao Yueqi Zhao Yang Xu Wang Yao Jinyi Tao Hao Wang Prof. Dr. Guangmin Yao Prof. Dr. Zimin Lu Prof. Dr. Jing Zeng Prof. Dr. Qian Wan 《Angewandte Chemie (International ed. in English)》2015,54(48):14432-14436
Latent O‐glycosides, 2‐(2‐propylthiol)benzyl (PTB) glycosides, were converted into the corresponding active glycosyl donors, 2‐(2‐propylsulfinyl)benzyl (PSB) glycosides, by a simple and efficient oxidation. Treatment of the PSB donor and various acceptors with triflic anhydride provided the desired glycosides in good to excellent yields. The leaving group, which was activated by an interrupted Pummerer reaction, can be recycled (PSB‐OH) and regenerated as the precursor (PTB‐OH). A natural hepatoprotective glycoside, leonoside F, was efficiently synthesized in a convergent [3+1] manner with this newly developed method. The present total synthesis also led to a structural revision of this phenylethanoid glycoside. 相似文献
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Generation of Sulfonyl Radicals from Aryldiazonium Tetrafluoroborates and Sulfur Dioxide: The Synthesis of 3‐Sulfonated Coumarins 下载免费PDF全文
Danqing Zheng Jiyao Yu Prof. Dr. Jie Wu 《Angewandte Chemie (International ed. in English)》2016,55(39):11925-11929
A catalyst‐free approach for the generation of sulfonyl radicals from aryldiazonium tetrafluoroborates in the presence of DABCO?(SO2)2 is realized. The combination of aryldiazonium tetrafluoroborates, DABCO?(SO2)2, and aryl propiolates affords 3‐sulfonated coumarins in good to excellent yields. This tandem reaction process involves radical addition, spirocyclization, and 1,2‐migration of esters. Additionally, the in situ diazotization of a number of anilines allows the directional synthesis of desired 3‐sulfonated coumarins in a one‐pot, two‐step process. 相似文献
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Dr. Marta K. Bruska Dr. Martin T. Stiebritz Prof. Dr. Markus Reiher 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):19081-19089
Reactive oxygen species (ROS) play an important role in the biochemistry of the cell and occur in degenerative processes as well as in signal transduction. Iron?sulfur proteins are particularly oxygen‐sensitive and their inorganic cofactors frequently undergo ROS‐induced decomposition reactions. As experimental knowledge about these processes is still incomplete we present here a quantum chemical study of the relative energetics for the binding of the most relevant ROS to [Fe4S4] clusters. We find that cubane clusters with one uncoordinated Fe atom (as found, for instance, in aconitase) bind all oxygen derivatives considered, whereas activation of triplet O2 to singlet O2 is required for binding to valence‐saturated iron centers in these clusters. The radicals NO and OH feature the most exothermic binding energies to Fe atoms. Direct sulfoxidation of coordinating cysteine residues is only possible by OH or H2O2 as attacking agents. The thermodynamic picture of ROS binding to iron?sulfur clusters established here can serve as a starting point for studying reactivity‐modulating effects of the cluster‐embedding protein environment on ROS‐induced decomposition of iron?sulfur proteins. 相似文献
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A Persulfide Donor Responsive to Reactive Oxygen Species: Insights into Reactivity and Therapeutic Potential 下载免费PDF全文
Chadwick R. Powell Kearsley M. Dillon Yin Wang Ryan J. Carrazzone John B. Matson 《Angewandte Chemie (International ed. in English)》2018,57(21):6324-6328
Persulfides (RSSH) have been hypothesized as critical components in sulfur‐mediated redox cycles and as potential signaling compounds, similar to hydrogen sulfide (H2S). Hindering the study of persulfides is a lack of persulfide‐donor compounds with selective triggers that release discrete persulfide species. Reported here is the synthesis and characterization of a ROS‐responsive (ROS=reactive oxygen species), self‐immolative persulfide donor. The donor, termed BDP‐NAC, showed selectivity towards H2O2 over other potential oxidative or nucleophilic triggers, resulting in the sustained release of the persulfide of N‐acetyl cysteine (NAC) over the course of 2 h, as measured by LCMS. Exposure of H9C2 cardiomyocytes to H2O2 revealed that BDP‐NAC mitigated the effects of a highly oxidative environment in a dose‐dependent manner over relevant controls and to a greater degree than common H2S donors sodium sulfide (Na2S) and GYY4137. BDP‐NAC also rescued cells more effectively than a non‐persulfide‐releasing control compound in concert with common H2S donors and thiols. 相似文献
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Metal‐Catalyzed “On‐Demand” Production of Carbonyl Sulfide from Carbon Monoxide and Elemental Sulfur 下载免费PDF全文
Wesley S. Farrell Peter Y. Zavalij Prof. Lawrence R. Sita 《Angewandte Chemie (International ed. in English)》2015,54(14):4269-4273
The group 6 molybdenum(II) cyclopentadienyl amidinate (CPAM) bis(carbonyl) complex [Cp*Mo{N(iPr)C(Ph)N(iPr)}(CO)2] (Cp*=η5‐C5Me5) serves as a precatalyst for the high‐yielding photocatalytic production of COS from CO and S8 under near‐ambient conditions (e.g., 10 psi, 25 °C). Further documented is the isolation and structural characterization of several key transition‐metal intermediates which collectively support a novel molybdenum(IV)‐based catalytic cycle as being operative. Finally, in the presence of an excess amount of a primary amine, it is demonstrated that this catalytic system can be successfully used for the “on‐demand” generation and utilization of COS as a chemical reagent for the synthesis of ureas. 相似文献
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A Free‐Radical‐Promoted Stereospecific Decarboxylative Silylation of α,β‐Unsaturated Acids with Silanes 下载免费PDF全文
Lizhi Zhang Zhaojia Hang Prof. Dr. Zhong‐Quan Liu 《Angewandte Chemie (International ed. in English)》2016,55(1):236-239
A stereospecific decarboxylative silylation of acrylic and propiolic acids with silanes was developed. This reaction represents the first example of decarboxylative C? Si bond formation and provides an efficient and convenient approach to various synthetically useful alkenyl and alkynyl organosilicon compounds through the reaction of α,β‐unsaturated acids with silanes. Spin‐trapping and EPR experiments support a radical addition/elimination process. 相似文献
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Jie‐Lian Han Ying Qin Cheng‐Wei Ju Dongbing Zhao 《Angewandte Chemie (International ed. in English)》2020,59(16):6555-6560
Organosilicon compounds have been extensively utilized both in industry and academia. Studies on the syntheses of diverse organosilanes is highly appealing. Through‐space metal/hydrogen shifts allow functionalization of C?H bonds at a remote site, which are otherwise difficult to achieve. However, until now, an aryl to alkyl 1,5‐palladium migration process seems to have not been presented. Reported herein is the remote olefination, arylation, and borylation of a methyl group on silicon to access diverse vinyl‐, benzyl‐, and borylsilanes, constituting a unique C(sp3)?H transformation based on a 1,5‐palladium migration process. 相似文献
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A General Approach to Site‐Specific,Intramolecular C−H Functionalization Using Dithiocarbamates 下载免费PDF全文
Christina G. Na Prof. Erik J. Alexanian 《Angewandte Chemie (International ed. in English)》2018,57(40):13106-13109
Intramolecular hydrogen atom transfer is an established approach for the site‐specific functionalization of unactivated, aliphatic C?H bonds. Transformations using this strategy typically require unstable intermediates formed using strong oxidants and have mainly targeted C?H halogenations or intramolecular aminations. Herein, we report a site‐specific C?H functionalization that significantly increases the synthetic scope and convergency of reactions proceeding via intramolecular hydrogen atom transfer. Stable, isolable N‐dithiocarbamates are used as precursors to amidyl radicals formed via either light or radical initiation to efficiently deliver highly versatile alkyl dithiocarbamates across a wide range of complex structures. 相似文献
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A Versatile and Highly Efficient Method for 1‐Chlorination of Terminal and Trialkylsilyl‐Protected Alkynes 下载免费PDF全文
Dr. Nurbey Gulia Bartłomiej Pigulski Marta Charewicz Dr. Sławomir Szafert 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(10):2746-2749
A highly efficient one‐pot procedure for the preparation of 1‐chloroalkynes and 1‐chlorobutadiynes from terminal and trialkylsilyl‐protected precursors is reported. This convenient reaction, proceeding under mild conditions, utilizes N‐chlorosuccinimide as the chlorinating agent and tolerates a range of functional groups. 相似文献
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Piotr Bałczewski Prof. Agnieszka Bodzioch Ewa Różycka‐Sokołowska Dr. Bernard Marciniak Dr. Paweł Uznański Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(8):2392-2400
A new concise approach for the construction of heteroatom analogues of polycyclic aromatic benzo[g]quinoline, benzo[b]carbazole, and pyrido[b]carbazole systems via diaryl methanols is described. This transformation involves formation of a central benzene ring fused to two aromatic 5‐ or 6‐membered rings of pyrrole and/or pyridine by using a combination of two aromatic aldehydes, of which at least one contains a ring nitrogen. Analysis of the UV and fluorescent properties, Stokes shifts, quantum yields in solution, and π‐stacking interactions in the crystal structures of the new materials was performed. These polycyclic aromatic compounds show potential as small‐molecule organoelectronic materials. 相似文献
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Zhenhua Sun Dr. Zhi Yang Dr. Jianhua Zhou Man Hau Yeung Weihai Ni Dr. Hongkai Wu Prof. Jianfang Wang Prof. 《Angewandte Chemie (International ed. in English)》2009,48(16):2881-2885
Cores and effect : Water‐dispersible core–shell structures and heterostructures incorporating gold nanocrystals of different shapes (polyhedra, cubes, and rods) and a variety of transition metal sulfide semiconductors (ZnS, CdS, NiS, Ag2S, and CuS) are synthesized using cetyltrimethylammonium bromide‐encapsulated gold nanocrystals and metal thiobenzoates as starting materials.