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Marek Humpl, Jiří Tauchman, Nikola Topolovčan, Jan Kretschmer, Filip Hessler, Ivana Císařová, Martin Kotora, Jan Veselý
Ru-catalyzed cross-metathesis (CM) reaction between β-arylated α-methylidene-β-lactams and terminal olefins was developed. The CM reaction is effectively catalyzed with Hoveyda-Grubbs second-generation catalyst affording corresponding α-alkylidene-β-aryl-β-lactams in good isolated yields (41-83%) with exclusive Z-selectivity. The developed protocol was successfully applied for stereoselective preparation of Ezetimibe, the commercial cholesterol absorption inhibitor.
September 2, 2016: Journal of Organic Chemistry
Nikola Topolovčan, Illia Panov, Martin Kotora
A three-step method based on Pd-catalyzed haloallylation of alkynes, Pd-catalyzed cross-coupling, and Ru-catalyzed ring-closing metathesis constitutes a new and short approach to variety of 1,2-substituted cyclopentadienes. The scope of the method is broad with respect to different substituents (alkyl, aryl, metallocenyl, and other substituents as well as their combinations are tolerated), and all steps proceeded with sensible yields. As a demonstration of product utility, several of the prepared cyclopentadienes were converted into the corresponding ferrocenes...
August 5, 2016: Organic Letters
Peter Kotora, František Šeršeň, Juraj Filo, Dušan Loos, Juraj Gregáň, Fridrich Gregáň
Resveratrol (3,5,4'-trihydroxystilbene) is a phytoalexin produced by plants. Resveratrol is known for its anti-cancer, antiviral and antioxidant properties. We prepared imine analogs of resveratrol ((hydroxyphenyliminomethyl)phenols) and tested their antioxidant activity. All prepared resveratrol analogs were able to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl radical (GOR) and 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS) radicals. The antioxidant activity efficiency correlated with the number and position of hydroxyl groups...
2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Aleš Machara, Vanda Lux, Milan Kožíšek, Klára Grantz Šašková, Ondřej Štěpánek, Martin Kotora, Kamil Parkan, Marcela Pávová, Bärbel Glass, Peter Sehr, Joe Lewis, Barbara Müller, Hans-Georg Kräusslich, Jan Konvalinka
Assembly of human immunodeficiency virus (HIV-1) represents an attractive target for antiretroviral therapy which is not exploited by currently available drugs. We established high-throughput screening for assembly inhibitors based on competition of small molecules for the binding of a known dodecapeptide assembly inhibitor to the C-terminal domain of HIV-1 CA (capsid). Screening of >70000 compounds from different libraries identified 2-arylquinazolines as low micromolecular inhibitors of HIV-1 capsid assembly...
January 28, 2016: Journal of Medicinal Chemistry
Joseph G Kotora
INTRODUCTION: Emergency healthcare providers are required to care for victims of Chemical, Biological, Radiologic, Nuclear, and Explosive (CBRNE) agents. However, US emergency departments are often ill prepared to manage CBRNE casualties. Most providers lack adequate knowledge or experience in the areas of patient decontamination, hospital-specific disaster protocols, interagency familiarization, and available supply of necessary medical equipment and medications. This study evaluated the CBRNE preparedness of physicians, nurses, and midlevel providers in an urban tertiary care emergency department...
2015: American Journal of Disaster Medicine
Joseph G Kotora
INTRODUCTION: Emergency healthcare providers are required to care for victims of Chemical, Biological, Radiologic, Nuclear, and Explosive (CBRNE) agents. However, US emergency departments are often ill prepared to manage CBRNE casualties. Most providers lack adequate knowledge or experience in the areas of patient decontamination, hospital-specific disaster protocols, interagency familiarization, and available supply of necessary medical equipment and medications. This study evaluated the CBRNE preparedness of physicians, nurses, and midlevel providers in an urban tertiary care emergency department...
September 2015: Journal of Emergency Management: JEM
Ivan Šnajdr, Kamil Parkan, Filip Hessler, Martin Kotora
Cross-metathesis of α- and β-vinyl C-deoxyribosides and α-vinyl C-galactoside with various terminal alkenes under different conditions was studied. The cross-metathesis of the former proceeded with good yields of the corresponding products in ClCH2CH2Cl the latter required the presence of CuI in CH2Cl2 to achieve good yields of the products. A simple method for the preparation of α- and β-vinyl C-deoxyribosides was also developed. In addition, feasibility of deprotection and further transformations were briefly explored...
2015: Beilstein Journal of Organic Chemistry
Reinhard P Kaiser, Filip Hessler, Jiří Mosinger, Ivana Císařová, Martin Kotora
Synthesis of selectively substituted fluorenes and fluorenols was achieved by using catalytic [2+2+2]cyclotrimerization. Various starting diynes were reacted with different alkynes in the presence of a catalytic amount of Wilkinson's catalyst (RhCl(PPh3)3) providing the compounds possessing the fluorene scaffold in good isolated yields. A set of four regioselectively substituted fluorenols was converted to the corresponding 9,9'-spirobifluorenes and their spectral characteristics were measured.
September 21, 2015: Chemistry: a European Journal
Petr Koukal, Martin Kotora
Allylation, trans- and cis-crotylation of (2E,4E)-2,4-dimethylhexadienal, a representative α,β,γ,δ-unsaturated aldehyde, was carried out under different catalytic and stoichiometric conditions. The reactions catalyzed by organocatalysts TRIP-PA and N,N'-dioxides gave the best results with respect to yields, asymmetric induction, and catalyst load in comparison to other procedures. The developed methodology was applied in the enantioselective synthesis of (5R,6S)-(+)-pteroenone, a defensive metabolite (ichthyodeterrent) of the Antarctic pteropod Clione antarctica...
May 11, 2015: Chemistry: a European Journal
Eva Prchalová, Ondřej Štěpánek, Stanislav Smrček, Martin Kotora
Compounds with polyfluorinated molecular fragments possess unique properties associated with the presence of a large number of fluorine atoms that affect lipophilicity and conformational rigidity of the parent molecule along with other effects. The aim of this review is to provide an overview of synthesized compounds possessing perfluoroalkylated or polyfluorinated chains that have been tested for bioactivity or as potential drug candidates for the treatment of various diseases. As far as the length of the perfluoroalkylated chain is concerned the focus is centered on the compound bearing perfluoroethyl or tetrafluoroethyl as well as longer chains...
June 2014: Future Medicinal Chemistry
Joseph G Kotora, Michael S Westrol, Mark A Merlin
OBJECTIVE: Accurate medical evaluation of victims injured during confined space rescues poses significant operational, medical, and logistical challenges for medical providers of all disciplines and experience levels. The Federal Emergency Management Agency (FEMA) teaches rescuers to begin their assessment as soon as verbal contact is obtained with the victim. While a significant amount of information can be obtained by talking to the victim, an accurate assessment of the victim's condition is often limited or impossible...
2014: American Journal of Disaster Medicine
Ivan Šnajdr, Zbyněk Janoušek, Masao Takagaki, Ivana Císařová, Narayan S Hosmane, Martin Kotora
The syntheses of the unprotected neutral closo-carboranyl-C-deoxyriboses, starting from anomeric mixture of 1-ethynyldeoxyriboses, and their corresponding open-cage nido-derivatives have been described. The structures of both the α- and β-anomers were confirmed by single-crystal X-ray diffraction. While limited water solubility of the neutral closo-anomers led to high cytotoxicity, their cesium salts (nido-species) exhibited higher water solubility leading to lower cytotoxicity. However, in vitro boron neutron capture therapy (BNCT) investigation using the murine squamous cell carcinoma (SCCVII) cell lines showed that there are no significant differences between the survival fractions of the two species...
August 18, 2014: European Journal of Medicinal Chemistry
Joseph G Kotora, Terry Clancy, Lauren Manzon, Varun Malik, Robert J Louden, Mark A Merlin
BACKGROUND: An active shooter in the emergency department (ED) presents a significant danger to employees, patients, and visitors. Very little education on this topic exists for healthcare workers. Using didactic and scenario-based training methods, the authors constructed a comprehensive training experience to better prepare healthcare workers for an active shooter. METHODS: Thirty-two residents, nurses, and medical students participated in a disaster drill onboard a US military base...
2014: American Journal of Disaster Medicine
Kamil Parkan, Radek Pohl, Martin Kotora
A convenient synthetic pathway enabling D-glucal and D-galactal pinacol boronates to be prepared in good isolated yields was achieved. Both pinacol boronates were tested in a series of cross-coupling reactions under Suzuki-Miyaura cross-coupling conditions to obtain the corresponding aryl, heteroaryl, and alkenyl derivatives in high isolated yields. This methodology was applied to the formal synthesis of the glucopyranoside moiety of papulacandin D and the first total synthesis of bergenin.
April 7, 2014: Chemistry: a European Journal
Joseph G Kotora, Jose Henao, Lanny F Littlejohn, Sara Kircher
BACKGROUND: Tension pneumothorax accounts for 3%-4% of combat casualties and 10% of civilian chest trauma. Air entering a wound via a communicating pneumothorax rather than by the trachea can result in respiratory arrest and death. In such cases, the Committee on Tactical Combat Casualty Care advocates the use of unvented chest seals to prevent respiratory compromise. OBJECTIVE: A comparison of three commercially available vented chest seals was undertaken to evaluate the efficacy of tension pneumothorax prevention after seal application...
November 2013: Journal of Emergency Medicine
John J Devlin, Sara S DeVito, Lanny F Littlejohn, Miguel A Gutierrez, Gosia Nowak, José Henao, Anthony Bielawski, Joseph Kotora, Andrew S Johnson
BACKGROUND: Principles of damage control resuscitation include minimizing intravenous fluid (IVF) administration while correcting perfusion pressure as quickly as possible. Recent studies have identified a potential advantage of vasopressin over catecholamines in traumatic shock. Terlipressin (TP) is a vasopressin analogue used to reverse certain shock etiologies in some European countries. STUDY OBJECTIVE: We evaluated three dosages of TP when combined with a limited colloid resuscitation strategy on mean arterial pressure (MAP) and lactatemia in a swine model of isolated hemorrhage...
July 2013: Journal of Emergency Medicine
Jamie S Johnson, Joseph G Kotora, Brett F Bechtel
Patients are often referred to the emergency department for further evaluation, yet the astute physician will maintain a broad differential to avoid anchoring on prior diagnoses. In this case, a 56-year-old man was referred to our emergency department from the radiology suite secondary to concerns for an “allergic reaction” to prior magnetic resonance imaging contrast. Upon presentation, he was noted to have facial swelling with ruddy appearance and vascular congestion extending to the midchest region; no airway compromise or dyspnea was noted...
November 2012: American Journal of Emergency Medicine
Filip Hessler, Ivana Císařová, David Sedlák, Petr Bartůněk, Martin Kotora
Ferrocenestrone, the first steroid derivative containing a metallocene moiety, was stereoselectively prepared. The key steps included the enantioselective functionalization of ferrocene, elongation of the side chain, intramolecular enyne metathesis, Diels-Alder reaction, heterogeneous hydrogenation of the sterically hindered double bond, and finally inversion of the configuration at C13.
April 27, 2012: Chemistry: a European Journal
Aleš Korotvička, Ivana Císařová, Jana Roithová, Martin Kotora
Substituted phenanthrenes and picenes were easily prepared by reaction of biphenylene or angular [3]phenylene with various alkynes in the presence of a catalytic amount of [IrCl(cod)](2) /dppe (cod=1,5-cyclooctadiene, dppe=1,2-bis(diphenylphosphino)ethane). The reaction is based on C-C bond activation of the cyclobutane ring. The reaction tolerates the presence of bulky groups on the alkyne, such as the ferrocene moiety. In addition, a catalytic system based on [RhCl(cod)](2)/dppe enabled the, hitherto unreported, reaction of biphenylene with nitriles to provide phenanthridines...
April 2, 2012: Chemistry: a European Journal
Brad L Bennett, Barbara Cailteux-Zevallos, Joseph Kotora
Challenges with surgical cricothyroidotomy on the battlefield can be attributed to limited frequency of use, procedure unfamiliarity, and limited knowledge base of anatomical landmarks of which is further heighten in the tactical environment. The objective was to identify ways to enhance the cricothyroidotomy training to minimize potential preventable procedural errors. A training review was conducted to determine the gaps in the cricothyroidotomy training in a 4-day Tactical Combat Casualty Care course at the Naval Medical Center Portsmouth...
November 2011: Military Medicine
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