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General Medicine and General Chemistry

Multidisciplinary

Organic Chemistry, Supramolecular chemistry, Spin chemistry, Chemistry (relationship), Electronic spin, High energy, Intellectual development, Physical organic chemistry, History of science, Chemistry, and Photochemistry

This Perspective presents a review and survey of the science and philosophy of my research career over the past five decades at Columbia as a physical organic chemist and photochemist. I explore the role of paradigms, structure, and geometric thinking in my own cognitive and intellectual development. The Perspective describes my investigations of high energy content molecules in electronically excited states and the development of electronic spin and supramolecular photochemistry chemistry. Current research dealing with the nuclear spin chemistry of H2 incarcerated in buckyballs is illustrated. In the second part of this Perspective, I recount a personal role of the philosophy and history of science and the scientific communities’ use of paradigms in their every day research and intellectual activities. Examples are given of the crucial role of geometry and structure in the rapid development of organic chemistry and physical organic chemistry over the past century.

Physical and Theoretical Chemistry, General Physics and Astronomy, General Chemistry, Quantum yield, Standard enthalpy of formation, Chemical nomenclature, Experimental data, Chemistry, Kinetic energy, Atmospheric chemistry, Photochemistry, Chemical kinetics, and Chemical reaction

This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997)]. The present evaluation is limited to the organic family of atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 171 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an Appendix listing the available values of enthalpies of formation of the reactant and product species.

Organic Chemistry, Anions, Cesium, Inorganic carbon compounds, Mixtures, Solvents, Química orgánica, and Chemistry, Organic

The diastereoselective synthesis of two families of pyrrolopiperazine-2,6-diones is presented. These compounds were prepared by one-pot Ugi/nucleophilic substitution/N-acylation/debenzoylation/(elimination) sequences. This novel route provides straightforward access to a wide variety of pyrrolopiperazine-2,6-diones with high chemical yields and complete diastereoselectivities. The proposed synthetic strategy poses a significant improvement compared to the syntheses of pyrrolopiperazine-2,6-diones previously described, as it allows introduction of different substituents to the C4 position and the diastereoselective generation of a new stereogenic center on the bridgehead carbon (C8a).
Funding from Consejería de Educación de la Junta de Castilla y León and FEDER (project BU075G19 and project BU067P20) and MCIN/AEI/10.13039/501100011033 (grant PID2020-117610RB-I00) is gratefully acknowledged. B.G.-S. and J.G.-A. thank Consejería de Educación de la Junta de Castilla y León for their predoctoral contracts. We also thank Inés María del Olmo for her contributions to the synthesis of some of the reported compounds.

General Chemistry, Science & Technology, Physical Sciences, Chemistry, Applied, Chemistry, Organic, Chemistry, Copper, Ullmann Reaction, C-N bond formation, kinetics, RPKA, COMPLEXES, AMINATION, PALLADIUM, DISCOVERY, MECHANISM, BCL-2, 0302 Inorganic Chemistry, 0305 Organic Chemistry, 0904 Chemical Engineering, and Organic Chemistry

A novel class of readily accessible tartramide ligands has been demonstrated to promote copper-catalysed N-arylation under mild conditions. In addition, the coupling protocol employs cheap and readily available pre-catalyst, ligand, and base (NaOH), and overcomes many current limitations often associated with Ullmann coupling: it can be run with low catalyst loadings, does not require the use of excess amine, gives excellent conversions at room temperature, is fully homogeneous, and displays improved tolerance to air and moisture. Detailed kinetic studies using reaction progress kinetic analysis (RPKA) methods have provided insight into the factors influencing the reaction rate in terms of impact of ligand structure, reactant / catalyst dependence and catalyst (in)stability. These kinetic insights have been used in a quality-by-design approach for further optimization of the reaction protocol. The reaction scope was extended to 22 examples, showing broad applicability for a wide range of substituted aryl iodides with both primary and secondary amines.

General Medicine, Monoamineoxidase,Chalcone,Propargyl,In vitro enzyme inhibition,Molecular docking, Monoaminoksidaz,Şalkon,Propargil,İn vitro enzim inhibisyonu,Moleküler docking, Mühendislik, Kimya, Engineering, Chemical, Biyoloji, Biology, Kimya, Organik, and Chemistry, Organic

Monoamine oxidases (MAO) are a family of enzymes responsible for the oxidative deamination of endogenous and exogenous amines. The MAO enzyme, which consists of two isoforms named MAO-A and MAO-B, are important targets in the development of drugs for the treatment of neuropsychiatric and neurodegenerative disorders due to their role in the metabolism of neurotransmitters. It is known that MAO-B inhibitors are frequently preferred in the treatment of the most common neurodegenerative diseases such as Parkinson's disease (PD) and Alzheimer's disease (AD). For this purpose, within the scope of this study, new propargyl-chalcone derivatives were synthesized and the structure determinations were elucidated using 1H-NMR, 13C-NMR and high-resolution mass spectroscopy (HRMS) methods. The data obtained as a result of in vitro activity tests showed that the compound 2c is promising as a selective MAO-B inhibitor. With the molecular modelling studies carried out, the binding and interaction points of the compound 2c in the hMAO-B enzyme active site were determined.
Monoamin oksidazlar (MAO), endojen ve ekzojen aminlerin oksidatif deaminasyonundan sorumlu enzim ailesidir. MAO-A ve MAO-B olarak isimlendirilen iki izoformdan oluşan MAO enzimi nörotransmiterlerin metabolizmasındaki rollerinden dolayı nöropsikiyatrik ve nörodejeneratif bozuklukların tedavisi için ilaçların geliştirilmesinde önemli hedeflerdir. Özellikle MAO-B inhibitörlerinin Parkinson hastalığı (PH) ve Alzheimer hastalığı (AH) gibi en sık görülen nörodejeneratif hastalıkların tedavisinde sıklıkla tercih edildiği bilinmektedir. Bu amaçla, bu çalışma kapsamında yeni propargil-şalkon türevleri sentezlenmiş ve yapı tayinleri 1H-NMR, 13C-NMR ve yüksek çözünürlüklü kütle spektroskopisi (HRMS) metotları kullanılarak aydınlatılmıştır. İn vitro aktivite testleri sonucunda elde edilen veriler 2c kodlu bileşiğin MAO-B inhibitörü olarak umut vaat edici olduğunu ortaya koymuştur. Gerçekleştirilen moleküler modelleme çalışmaları ile bileşik 2c’nin hMAO-B enzim aktif bölgesindeki bağlanma ve etkileşim noktaları belirlenmiştir.

Pollution, Environmental Chemistry, Química orgánica, Bioquímica, Chemistry, Organic, and Biochemistry

Selection of the appropriate base in Ugi/post-condensation sequences allows the selective syntheses of different ring-size functionalized lactams. The developed methodology uses inexpensive bases under mild and non-sensitive conditions leading to the facile generation of molecular diversity from simple synthons. Funding from Consejería de Educación de la Junta de Castilla y León and European Regional Development Fund (ERDF) (project BU075G19 and project BU067P20) and MCIN/AEI/10.13039/501100011033 [grant PID2020-117610RB-I00] is gratefully acknowledged. B. G.-S. and I. C.-B. thank Consejería de Educación de la Junta de Castilla y León, European Social Fund (ESF) and ERDF for their predoctoral (B. G.-S) and postdoctoral (I. C.-B.) contracts.