Role of Sterically Demanding Chiral Dirhodium Catalysts in Site-Selective C–H Functionalization of Activated Primary C–H Bonds

2014 ◽  
Vol 136 (27) ◽  
pp. 9792-9796 ◽  
Author(s):  
Changming Qin ◽  
Huw M. L. Davies
Keyword(s):  
Sterically Demanding ◽  
Site Selective ◽  
Dirhodium Catalysts

Role of site-selective cAMP analogs in the control and reversal of malignancy

1991 ◽  
Vol 50 (1) ◽  
pp. 1-33 ◽  
Author(s):  
Yoon S. Cho-Chung ◽  
Timothy Clair ◽  
Giampaolo Tortora ◽  
Hiroshi Yokozaki
Keyword(s):  
Site Selective

Site-Selective Analysis of Nickel-Substituted Li-Rich Layered Material: Migration and Role of Transition Metal at Charging and Discharging

2018 ◽  
Vol 122 (35) ◽  
pp. 20099-20107 ◽  
Author(s):  
Hideyuki Komatsu ◽  
Taketoshi Minato ◽  
Toshiyuki Matsunaga ◽  
Keiji Shimoda ◽  
Tomoya Kawaguchi ◽  
...  
Keyword(s):  
Transition Metal ◽  
Layered Material ◽  
Material Migration ◽  
Site Selective ◽  
Selective Analysis

Site-Selective Multi-Stacked Assembly of Silver Nanoparticles on Amine-Functionalized Printed Patterns: Comparative Studies on the Role of Electrostatic Interaction and Meniscus

2015 ◽  
Vol 2 (11) ◽  
pp. 1500129 ◽  
Author(s):  
Aryeon Kim ◽  
Yejin Jo ◽  
Jong Chan Won ◽  
Youngmin Choi ◽  
Kwang-Suk Jang ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Electrostatic Interaction ◽  
Comparative Studies ◽  
Amine Functionalized ◽  
Printed Patterns ◽  
Site Selective

scholarly journals Role of Macrocyclic Conformational Steering in a Kinetic Route toward Bielschowskysin

2020 ◽  
Author(s):  
Paul Scesa ◽  
Lyndon M. West ◽  
Stephane Roche
Keyword(s):  
Natural Products ◽  
Selective Oxidation ◽  
Synthetic Methods ◽  
Kinetic Control ◽  
Kinetically Controlled ◽  
Conformational Preferences ◽  
Stereoselective Epoxidation ◽  
Site Selective

Macrocyclic furanobutenolide-derived cembranoids (FBCs) are the biosynthetic precursors to a wide variety of highly congested and oxygenated polycyclic (nor)diterpenes (<i>e.g.</i> plumarellide, verrillin or bielschowskysin). These architecturally complex metabolites are thought to originate from site-selective oxidation of the macrocycles’ backbone and a series of intricate transannular reactions. Yet the development of a common biomimetic route has been hampered by a lack of synthetic methods for the pivotal furan dearomatization in a regio- and stereoselective manner. To address these shortcomings, a concise strategy of chemo- and stereoselective epoxidation followed by a kinetically-controlled furan dearomatization is reported. The surprising switch of facial <i>a</i>:<i>b</i>-discrimination observed in the epoxidations of the most strained <i>E</i>-acerosolide <i>versus</i> <i>E</i>-deoxypukalide and <i>E</i>-bipinnatin J derived macrocycles has been rationalized by the 3D-conformational preferences of the macrocyclic scaffolds. The downstream functionalization of FBC-macrocycles was also studied, and how the C-7 epoxide configuration was retentively translated to the C-3 stereogenicity in dearomatized products under kinetic control to secure the requisite (3<i>S</i>,7<i>S</i>,8<i>S</i>)-configurations for the bielschowskysin synthesis. Unlike previously speculated, our results suggest that the most strained FBC-macrocycles bearing a <i>E</i>-(D<sup>7,8</sup>)-alkene moiety may stand as the true biosynthetic precursors to bielschowskysin and several other polycyclic natural products of this class.

Abstract 16797: Mechanisms That Repress BMP2 in Mesenchymal Cells

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Melissa Rogers ◽  
Anastasios Fotinos ◽  
Tapan Shah
Keyword(s):  
Binding Sites ◽  
Heart Valves ◽  
Protein A ◽  
Mesenchymal Cells ◽  
Regulatory Proteins ◽  
Conserved Sequence ◽  
Pathological Calcification ◽  
Site Selective ◽  
Mirna Seed

BMP2 is an essential protein. A short burst of BMP2 promotes repair after vascular injury. However, excessive BMP2 levels in the vasculature and heart valves promote pathological calcification. A sequence within the 3’UTR of the mRNA termed the “ultra-conserved sequence” (UCS) has been largely unchanged since fishes and mammals diverged. Cre-lox mediated deletion of the UCS in a mouse reporter transgene revealed that one role of the UCS is to repress BMP2 synthesis in heart valves and vascular cells. We are now testing the hypothesis that normal heart morphology requires UCS-mediated restraint of BMP2 synthesis. We used homologous recombination to generate a Bmp2 allele with the endogenous Bmp2 UCS flanked by loxP sites. We bred this strain to strains that express Cre-recombinase thus deleting the UCS. The survival of pups with homozygous loss of the UCS was significantly reduced. We are now assessing embryonic heart morphology in these strains. We also postulate that the regulatory proteins and microRNAs that mediate UCS-mediated repression may be exploited to pharmacologically reawaken BMP2 repression in tissues undergoing pathological pathologies. Specific miRNAs inhibit UCS-bearing reporters and mutations of miRNA binding sites activate these reporters. Interestingly, an A+U rich element (ARE) known to bind HuR (generally an activator) and AUF1 (a repressor) is embedded in a conserved miRNA binding site. Selective mutations of the ARE and the miRNA seed indicate that repressive molecules bind this site in mesenchymal cells where the UCS functions as a repressor.

Site-Selective Dissociation Processes of Cationic Ethanol Conformers: The Role of Hyperconjugation

2014 ◽  
Vol 118 (34) ◽  
pp. 7096-7103
Author(s):  
Weixing Li ◽  
Yongjun Hu ◽  
Fuyi Liu ◽  
Xiaobin Shan ◽  
Liusi Sheng
Keyword(s):  
Selective Dissociation ◽  
Site Selective

scholarly journals Electrophoretic Deposition of WS2 Flakes on Nanoholes Arrays—Role of Used Suspension Medium

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3286 ◽  
Author(s):  
Dario Mosconi ◽  
Giorgia Giovannini ◽  
Nicolò Maccaferri ◽  
Michele Serri ◽  
Stefano Agnoli ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Deposition Process ◽  
Plasmonic Nanostructures ◽  
Selective Deposition ◽  
Ordered Arrays ◽  
Plasmonic Structures ◽  
The Stability ◽  
Site Selective ◽  
Integrated Structures

Here we optimized the electrophoretic deposition process for the fabrication of WS2 plasmonic nanohole integrated structures. We showed how the conditions used for site-selective deposition influenced the properties of the deposited flakes. In particular, we investigated the effect of different suspension buffers used during the deposition both in the efficiency of the process and in the stability of WS2 flakes, which were deposited on an ordered arrays of plasmonic nanostructures. We observed that a proper buffer can significantly facilitate the deposition process, keeping the material stable with respect to oxidation and contamination. Moreover, the integrated plasmonic structures that can be prepared with this process can be applied to enhanced spectroscopies and for the preparation of 2D nanopores.

scholarly journals Novel fidaxomicin antibiotics through site-selective catalysis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
David Dailler ◽  
Andrea Dorst ◽  
Daniel Schäfle ◽  
Peter Sander ◽  
Karl Gademann
Keyword(s):  
Rational Design ◽  
Antibacterial Properties ◽  
Structural Diversity ◽  
Antibacterial Activities ◽  
Resistance Development ◽  
Gram Positive Bacteria ◽  
Clostridioides Difficile ◽  
Pharmacokinetic Properties ◽  
Site Selective

AbstractFidaxomicin (FDX) is a marketed antibiotic for the treatment of Clostridioides difficile infections (CDI). Fidaxomicin displays antibacterial properties against many Gram-positive bacteria, yet the application of this antibiotic is currently limited to treatment of CDI. Semisynthetic modifications present a promising strategy to improve its pharmacokinetic properties and also circumvent resistance development by broadening the structural diversity of the derivatives. Here, based on a rational design using cryo-EM structural analysis, we implement two strategic site-selective catalytic reactions with a special emphasis to study the role of the carbohydrate units. Site-selective introduction of various ester moieties on the noviose as well as a Tsuji–Trost type rhamnose cleavage allow the synthesis of novel fidaxomicin analogs with promising antibacterial activities against C. difficile and Mycobacterium tuberculosis.

Crucial role of linker portion in acridine-bearing oligonucleotides for highly efficient site-selective RNA scission

2004 ◽  
Vol 45 (19) ◽  
pp. 3703-3706 ◽  
Author(s):  
Yun Shi ◽  
Akinori Kuzuya ◽  
Kenzo Machida ◽  
Makoto Komiyama
Keyword(s):  
Crucial Role ◽  
Highly Efficient ◽  
Site Selective
Sign in / Sign up

Export Citation Format

Share Document