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PD Access

Nitin Chakravarti, Doina Ivan, Van A Trinh, Isabella C Glitza, Jonathan L Curry, Carlos Torres-Cabala, Michael T Tetzlaff, Roland L Bassett, Victor G Prieto, Wen-Jen Hwu
Ipilimumab, a fully human monoclonal antibody against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), is the first immune checkpoint inhibitor approved for the treatment of unresectable melanoma on the basis of its overall survival (OS) benefit. However, ipilimumab is associated with significant immune-related adverse events. We hypothesized that biomarker exploration of pretreatment tumor samples and correlation with clinical outcome would enable patient selection with an increased benefit/risk ratio for ipilimumab therapy...
October 20, 2016: Melanoma Research
Michael Grigalunas, Olaf Wiest, Paul Helquist
Trisubstituted α-pyrones are obtained by a Pd-catalyzed three-component, single-flask operation via an α-arylation, subsequent α-alkenylation, alkene isomerization, and dienolate lactonization. A variety of coupling components under mild conditions afforded isolated yields of up to 93% of the pyrones with complete control of regioselectivity. Metal dependence was noted for three of the steps of the pathway. Utility of the pyrone products was demonstrated by further transformations providing convenient access to polyaromatic compounds, exhibiting broad molecular diversity...
October 21, 2016: Organic Letters
Chao Cheng, Wen-Wen Chen, Bin Xu, Ming-Hua Xu
A base-free process to access indole-fused polyheterocycles via a highly efficient and atom-economic palladium-catalyzed intramolecular cross dehydrogenetive coupling (CDC) reaction of 4-aniline substituted coumarins, quinolinones and pyrones has been developed. A wide range of indolo[3,2-c]coumarins, indolo[3,2-c]quinolinones and indolo[3,2-c]pyrones can be facilely afforded in good to excellent yields (up to 99%).
October 21, 2016: Journal of Organic Chemistry
Jérémie Grolleau, Frédéric Gohier, Clément Cabanetos, Magali Allain, Stéphanie Legoupy, Pierre Frère
Synthetic access to new push-pull molecules based on 3-cyano-4-hexyloxythiophene and triphenylamine moieties is presented herein using a clean methodology. The key step involves a direct heteroarylation coupling reaction in the presence of a homogeneous or heterogeneous [Pd] catalyst followed by Knoevenagel condensation performed in ethanol as a solvent. Structure-electronic property relationships of the new molecular materials are discussed and then their use as donors in bilayer planar heterojunction solar cells is investigated...
October 21, 2016: Organic & Biomolecular Chemistry
Anna C Giddens, Ho H Lee, Guo-Liang Lu, Christian K Miller, Jun Guo, Gail D Lewis Phillips, Thomas H Pillow, Moana Tercel
A Pd-catalysed amination method is used to convert seco-CBI, a synthetic analogue of the alkylating subunit of the duocarmycin natural products, from the phenol to amino form. This allows efficient enantioselective access to the more potent S enantiomer of aminoCBI and its incorporation into analogues of DNA minor groove cross-linking agents. Evaluation in a panel of nine human tumour cell lines shows that the bifunctional agents containing aminoCBI are generally less cytotoxic than their phenolCBI analogues and more susceptible to P-glycoprotein-mediated resistance...
September 30, 2016: Bioorganic & Medicinal Chemistry
Vanessa J Bukas, Karsten Reuter
We augment ab initio molecular dynamics simulations with a quantitative account of phononic dissipation to study the hyperthermal adsorbate dynamics resulting from a noninstantaneous energy dissipation during exothermic surface chemical reactions. Comparing the hot adatom diffusion ensuing O_{2} dissociation over Pd(100) and Pd(111) we find experimentally accessible product end distances to form a rather misleading measure for the lifetime of this hyperthermal state. The lifetime is particularly long at Pd(111) where a random-walk-type diffusion leads only to small net displacements...
September 30, 2016: Physical Review Letters
Dalip Kumar, V Arun, Meenakshi Pilania
Easily accessible heteroaromatic carboxylic acids and diaryliodonium salts were successfully employed to construct valuable 2-arylindoles and heteroaryl carboxylates in a regioselective fashion. C2-arylated indoles were produced via Pd-catalyzed decarboxylative strategy in water without any base, oxidant and ligand. Heteroaryl carboxylates were prepared under metal and base-free conditions. This protocol was successfully utilized to synthesize Paullone, a CDK inhibitor.
October 13, 2016: Chemistry, An Asian Journal
Danny Schuhknecht, Florian Ritter, Michael E Tauchert
The palladium diphosphinoboryl pincer [{(o-PPh2C6H4)2B}Pd(II)I] 8 was prepared from the diphosphinoborane complex 6a. The boryl functionality of the pincer displayed ambiphilic properties allowing: (1) coordination of Lewis basic pyridines to the boryl site and (2) access to palladium diphosphinoborane complex derivatives.
September 27, 2016: Chemical Communications: Chem Comm
Dr Dharmendra Kanoriya, Dr A R Pradeep, Dr Vibhuti Garg, Dr Sandeep Singhal
BACKGROUND: Different materials have been instigated for renewal of lost supporting periodontal structures and tested for furcation defects treatment. Platelet-rich fibrin (PRF) is a pool of growth promoting factors and cytokines which promotes bone regeneration and maturation of soft tissue. Alendronate (ALN), an influential member of bisphosphonate group is known to enhance osteoblastogenesis and inhibits osteoclastic bone resorption, thus promoting tissue regeneration. This randomized trial was done to assess the effectiveness of PRF and 1% ALN gel combination in mandibular degree II furcation defects treatment in comparison to PRF and access therapy alone...
October 7, 2016: Journal of Periodontology
Helene Strauch, Jörn Engelmann, Klaus Scheffler, Hermann A Mayer
A fast and simple route was developed to synthesize a new T8-silsesquioxane based contrast agent for potential application in Magnetic Resonance Imaging. For this purpose the novel C2-thiol-functionalized T8-silsesquioxane (3) was constructed as a carrier molecule as well as the DOTA based gadolinium(iii) complex (11) equipped with allyl terminated linkers was prepared. The linkage of the complexes to the T8-silsesquioxane was performed via an UV-light catalyzed thiol-ene click reaction within one hour which affords the desired product 13 in a yield of 80%...
September 27, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Christine M Le, Theresa Sperger, Rui Fu, Xiao Hou, Yong Hwan Lim, Franziska Schoenebeck, Mark Lautens
We report a highly robust, general and stereoselective method for the synthesis of 3-(chloromethylene)oxindoles from alkyne-tethered carbamoyl chlorides using PdCl2(PhCN)2 as the catalyst. The transformation involves a stereo- and regioselective chloropalladation of an internal alkyne to generate a nucleophilic vinyl Pd(II) species, which then undergoes an intramolecular cross-coupling with a carbamoyl chloride. The reaction proceeds under mild conditions, is insensitive to the presence of moisture and air, and is readily scalable...
October 4, 2016: Journal of the American Chemical Society
George A Heckman, Alexander M Crizzle, Jonathen Chen, Tamara Pringsheim, Nathalie Jette, Marie-Jeanne Kergoat, Leslie Eckel, John P Hirdes
BACKGROUND: Patients with Parkinson's disease (PD) and/or Parkinsonism are affected by a complex burden of comorbidity. Many ultimately require institutional care, where they may be subject to the application of physical restraints or the prescription of antipsychotic medications, making them more vulnerable to adverse outcomes. OBJECTIVES: The objectives of this paper are to: 1) describe the clinical complexity of older institutionalized persons with PD; and 2) examine patterns and predictors of restraint use and prescription of antipsychotics in this population...
September 29, 2016: Journal of Parkinson's Disease
Shi Chen, Mukulesh Mondal, Ahmad A Ibrahim, Kraig A Wheeler, Nessan J Kerrigan
A highly diastereoselective approach to dipropionate derivatives through Pd/C-catalyzed hydrogenation of enantioenriched E-ketene heterodimers is described. Catalytic hydrogenation of the E-isomer of ketene heterodimer β-lactones (12 examples) provides access to syn,anti-β-lactones (dipropionate derivatives) bearing up to three stereogenic centers (dr up to 49:1), and with excellent transfer of chirality (ee up to >99%).
August 2016: Synthesis
Yue-Jin Liu, Yan-Hua Liu, Zhuo-Zhuo Zhang, Sheng-Yi Yan, Kai Chen, Bing-Feng Shi
A general and practical Pd(II) -catalyzed intermolecular silylation of primary and secondary C-H bonds of α-amino acids and simple aliphatic acids is reported. This method provides divergent and stereoselective access to a variety of optical pure β-silyl-α-amino acids, which are useful for genetic technologies and proteomics. It can also be readily performed on a gram scale and the auxiliary can be easily removed with retention of configuration. The synthetic importance of this method is further demonstrated by the late-stage functionalization of biological small molecules, such as (-)-santonin and β-cholic acid...
October 24, 2016: Angewandte Chemie
Beau P Pritchett, Jun Kikuchi, Yoshitaka Numajiri, Brian M Stoltz
The successful application of dihydropyrido[1,2-a]indolone (DHPI) substrates in Pd-catalyzed asymmetric allylic alkylation chemistry facilitates rapid access to multiple alkaloid frameworks in an enantioselective fashion. Strategic bromination at the indole C3 position greatly improved the allylic alkylation chemistry and enabled a highly efficient Negishi cross-coupling downstream. The first catalytic enantioselective total synthesis of (-)-goniomitine, along with divergent formal syntheses of (+)-aspidospermidine and (-)-quebrachamine, are reported herein...
October 17, 2016: Angewandte Chemie
Jianchao Liu, Hui Peng, Yongjie Yang, Huanfeng Jiang, Biaolin Yin
Herein, we report regio- and stereoselective intramolecular direct arylations of N-(2-bromophenyl)-2-furancarboxamides 1 to produce spirooxindoles 2 and 5H-furo[2,3-c]quinolin-4-ones 3 under different reaction conditions. Specifically, in the presence of Pd(PPh3)4 as a catalyst, PPh3 as a ligand, and K2CO3 as a base, substrates 1 underwent intramolecular α-arylation, possibly via a Heck insertion pathway, to provide 2, with the Z-isomer being favored. When the base was t-BuOLi and R(1) was an aryl group, the reaction favored E-2, possibly via an electrophilic palladation pathway...
October 3, 2016: Journal of Organic Chemistry
Katie J Seidler, Ryan P Duncan, Marie E McNeely, Madeleine E Hackney, Gammon M Earhart
People with Parkinson disease (PD) demonstrate improvements in motor function following group tango classes, but report long commutes as a barrier to participation. To increase access, we investigated a telerehabilitation approach to group tango instruction. Twenty-six people with mild-to-moderate PD were assigned based on commute distance to either the telerehabilitation group (Telerehab) or an in-person instruction group (In-person). Both groups followed the same twice-weekly, 12-week curriculum with the same instructor...
September 13, 2016: Journal of Telemedicine and Telecare
Ji-Soo Jang, Sunmoon Yu, Seon-Jin Choi, Sang-Joon Kim, Won-Tae Koo, Il-Doo Kim
Rational design of nanostructures and efficient catalyst functionalization methods are critical to the realization of highly sensitive gas sensors. In order to solve these issues, two types of strategies are reported, i.e., (i) synthesis of peapod-like hollow SnO2 nanostructures (hollow 0D-1D SnO2 ) by using fluid dynamics of liquid Sn metal and (ii) metal-protein chelate driven uniform catalyst functionalization. The hollow 0D-1D SnO2 nanostructures have advantages in enhanced gas accessibility and higher surface areas...
September 13, 2016: Small
Jason W Schultz, Kei Fuchigami, Bo Zheng, Nigam P Rath, Liviu M Mirica
Nickel-catalyzed cross-coupling reactions are experiencing a dramatic resurgence in recent years given their ability to employ a wider range of electrophiles as well as promote stereospecific or stereoselective transformations. In contrast to the extensively studied Pd catalysts that generally employ diamagnetic intermediates, Ni systems can more easily access various oxidation states including odd-electron configurations. For example, organometallic Ni(III) intermediates with aryl and/or alkyl ligands are commonly proposed as the active intermediates in cross-coupling reactions...
October 5, 2016: Journal of the American Chemical Society
Kangway V Chuang, Madeleine E Kieffer, Sarah E Reisman
A mild and general protocol for the Pd(0)-catalyzed heteroannulation of o-bromoanilines and alkynes is described. Application of a Pd(0)/P((t)Bu)3 catalyst system enables the efficient coupling of o-bromoanilines at 60 °C, mitigating deleterious side reactions and enabling access to a broad range of useful unnatural tryptophans. The utility of this new protocol is demonstrated in the highly convergent total synthesis of the bisindole natural product (-)-aspergilazine A.
September 16, 2016: Organic Letters
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