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Dr. Nina Schützenmeister Dr. Michael Müller Prof. Dr. Uwe M. Reinscheid Prof. Dr. Christian Griesinger Dr. Andrei Leonov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17584-17588
Here we report the synthesis of all four stereoisomers of mefloquine. Mefloquine (Lariam) is an important anti‐malaria drug that is applied as a racemate of the erythro form. However, the (?)‐isomer induces psychosis, while the (+)‐enantiomer does not have this undesired side effect. There are six syntheses of which five lead to the wrong enantiomer without the authors of these syntheses noting that they had synthesized the wrong compound. At the same time physical chemistry investigations had assigned the absolute configuration correctly and the last enantioselective synthesis that took these results into account delivered the correct absolute configuration. Since various synthetic approaches failed to provide the correct stereoisomers in previous syntheses, we submit here a synthetic approach with a domino Sonogashira‐6π‐electrocyclisation as key step that confirmed synthetically the correct absolute configuration of all four isomers. 相似文献
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Palladium‐Catalyzed Stereoselective Intramolecular Oxidative Amidation of Alkenes in the Synthesis of 1,3‐ and 1,4‐Amino Alcohols and 1,3‐Diamines 下载免费PDF全文
Prof. Dr. Andrei V. Malkov Dr. Darren S. Lee Dr. Maciej Barłóg Dr. Mark R. J. Elsegood Prof. Dr. Pavel Kočovský 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):4901-4905
An efficient and practical Pd‐catalyzed intramolecular oxidative allylic amidation provides facile access to derivatives of 1,3‐ and 1,4‐amino alcohols and 1,3‐diamines. The method operates under mild reaction conditions (RT) with molecular oxygen (1 atm) as the sole reoxidant of Pd. Excellent diastereoselectivities were attained with substrates bearing a secondary stereogenic center 相似文献
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Mikhail V. Vener Andrei V. Churakov Alexander P. Voronin Olga D. Parashchuk Sergei V. Artobolevskii Oleg A. Alatortsev Denis E. Makhrov Alexander G. Medvedev Aleksander Filarowski 《Molecules (Basel, Switzerland)》2022,27(3)
Two new peroxosolvates of drug-like compounds were synthesized and studied by a combination of X-ray crystallographic, Raman spectroscopic methods, and periodic DFT computations. The enthalpies of H-bonds formed by hydrogen peroxide (H2O2) as a donor and an acceptor of protons were compared with the enthalpies of analogous H-bonds formed by water (H2O) in isomorphic (isostructural) hydrates. The enthalpies of H-bonds formed by H2O2 as a proton donor turned out to be higher than the values of the corresponding H-bonds formed by H2O. In the case of H2O2 as a proton acceptor in H-bonds, the ratio appeared reversed. The neutral O∙∙∙H-O/O∙∙∙H-N bonds formed by the lone electron pair of the oxygen atom of water were the strongest H-bonds in the considered crystals. In the paper, it was found out that the low-frequency Raman spectra of isomorphous crystalline hydrate and peroxosolvate of N-(5-Nitro-2-furfurylidene)-1-aminohydantoin are similar. As for the isostructural hydrate and peroxosolvate of the salt of protonated 2-amino-nicotinic acid and maleic acid monoanion, the Raman spectra are different. 相似文献
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Andrei Gaidash Anton Kozubov Svetlana Medvedeva George Miroshnichenko 《Entropy (Basel, Switzerland)》2020,22(12)
In this paper, we consider the influence of a divergence of polarization of a quantum signal transmitted through an optical fiber channel on the quantum bit error rate of the subcarrier wave quantum key distribution protocol. Firstly, we investigate the dependence of the optical power of the signal on the modulation indices’ difference after the second phase modulation of the signal. Then we consider the Liouville equation with regard to relaxation in order to develop expressions of the dynamics of the Stokes parameters. As a result, we propose a model that describes quantum bit error rate for the subcarrier wave quantum key distribution depending on the characteristics of the optical fiber. Finally, we propose several methods for minimizing quantum bit error rate. 相似文献
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Although conventional medicine, chemical drug synthesis and pharmaceutical research are advancing at a rapid pace, nature remains a major supplier of biological molecules. Natural bioactive compounds are studied closely especially as an alternative to the limitations of conventional therapy in many diseases, melanoma being one of them. Malignant melanoma is a highly aggressive type of cancer, and the current methods of treatment used are cryotherapy, external surgery, radiation therapy, chemotherapy, photodynamic therapy, biological therapy, and targeted drug therapy. Unfortunately, these treatment methods are often inefficient, extremely expensive and cause many side effects, which is why focusing on melanoma chemoprevention and adjuvant therapy with natural herbal phytoconstituents is an emerging strategy to prevent, cure or treat melanoma. This review aims to examine the latest discoveries in terms of potential natural bioactive compounds that possess important activity against the development and spread of murine melanoma cancer. In particular, the use of different phytochemicals such as phenolic acids, flavonoids, anthocyanins, terpenoids, essential oils and carotenoids in vitro and in vivo models will be discussed. These data are helpful in guiding researchers in the direction of studying phytonutrients with important effects in the prevention and treatment of melanoma. 相似文献
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We find sufficient conditions for the absence of harmonic L 2 spinors on spin manifolds constructed as cone bundles over a compact Kähler base. These conditions are fulfilled for certain perturbations of the Euclidean metric, and also for the generalized Taub-NUT metrics of Iwai-Katayama, thus proving a conjecture of Vi?inescu and the second author. 相似文献
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