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A facile synthetic route of linezolid 1 has been developed.Using commercially available(R)epichlorohydrin as the starting material,1 was obtained through a sequence of cyclization,substitution, a Goldberg coupling,aminolysis and acetylation reactions.The synthetic route is easy to perform and can be scaled up. 相似文献
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Let G be a bridgeless cubic graph. Consider a list of k 1‐factors of G. Let be the set of edges contained in precisely i members of the k 1‐factors. Let be the smallest over all lists of k 1‐factors of G. We study lists by three 1‐factors, and call with a ‐core of G. If G is not 3‐edge‐colorable, then . In Steffen (J Graph Theory 78 (2015), 195–206) it is shown that if , then is an upper bound for the girth of G. We show that bounds the oddness of G as well. We prove that . If , then every ‐core has a very specific structure. We call these cores Petersen cores. We show that for any given oddness there is a cyclically 4‐edge‐connected cubic graph G with . On the other hand, the difference between and can be arbitrarily big. This is true even if we additionally fix the oddness. Furthermore, for every integer , there exists a bridgeless cubic graph G such that . 相似文献
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AbstractIn the present paper, we summarize the recent literature concerning the spectrum and fine spectrum with respect to Goldberg’s classification of some operators represented by an infinite matrix over certain sequence spaces. 相似文献
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Vinzenz Thönnißen Prof. Dr. Frederic W. Patureau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(25):7189-7192
The atroposelective formation of C−N bonds has recently emerged within the field of amination reactions. On first sight, it may seem quite surprising that such an ancient class of organic coupling reactions (Gabriel, Ullmann, Goldberg, Buchwald, Hartwig and many others) has so few enantioselective solutions, and this in spite of asymmetric synthesis being now a mature concept and field. Why should enantioselective C−N bond formation be so difficult? This question and some of the first examples that promise an imminent change of paradigm are herein discussed. 相似文献
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Mohammad Ghebleh 《Discrete Mathematics》2007,307(24):3220-3225
We determine the exact values of the circular chromatic index of the Goldberg snarks, and of a related family, the twisted Goldberg snarks. 相似文献
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A short and economical synthesis of various 2-methylaminopyidine amides (MAPA) from 2-bromopyridine has been developed using the catalytic Goldberg reaction. The effective catalyst was formed in situ by the reaction of CuI and 1,10-phenanthroline in a 1/1 ratio with a final loading of 0.5–3 mol%. The process affords high yields and can accommodate multigram-scale reactions. A modification of this method provides a new preparation of 2-N-substituted aminopyridines from various secondary N-alkyl(aryl)formamides and 2-bromopyridine. The intermediate aminopyridine formamide is cleaved in situ through methanolysis or hydrolysis to give 2-alkyl(aryl)aminopyridines in high yields. 相似文献
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A novel and highly selective silver-promoted monobenzylation method was developed to promote synthesis of nonsymmetrical sulfamide-based HIV-1 inhibitors. Microwave-accelerated palladium-catalyzed N-amide arylation- and aminocarbonylation reactions were employed for rapid and reliable compound generation. With this class of inhibitory agents, six active inhibitors were identified, the most potent inhibitor possessing a Ki-value of 20 nM. 相似文献
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Fulkersonʼs Conjecture says that every bridgeless cubic graph has six perfect matchings such that each edge belongs to exactly two of them. In 1976, F. Loupekine created a method for constructing new snarks from already known ones. We consider an infinite family of snarks built with Loupekineʼs method, and verify Fulkersonʼs Conjecture for this family. 相似文献
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A highly general, experimentally simple, and inexpensive catalyst system was developed for the amidation of aryl iodides by using 5 mol % of CuI as catalyst, 20 mol % of an amino acid as ligand, and K3PO4 as base. 相似文献