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151.
A total synthesis of (-)-kainic acid starting from the commercially available 2-azetidinone is described. The key delta-lactone intermediate was concisely prepared from the commercially available azetidinone through the Reformatsky-type reaction and an introduction of a glycine moiety. The construction of the functionalized pyrrolidine ring was executed by a one-pot sequential elimination-Michael addition protocol of a beta-amino-delta-lactone intermediate with high diastereoselectivity. 相似文献
152.
A concise synthesis of maremycins A and D1 has been accomplished via cycloaddition of a chiral cyclic nitrone with ( E)-3-ethylidene-1-methylindolin-2-one as a key step. This synthesis clarifies the stereochemistry of the maremycins and is suitable for large-scale synthesis for biological screening. 相似文献
153.
A unique combination of CuI and CsOAc was found to catalyze aryl amination under mild conditions. The reaction takes place at room temperature or at 90 °C with broad functional group compatibility. The intramolecular reaction was able to form five-, six-, and seven-membered rings with various protecting groups on the nitrogen atom. The scope of the intermolecular amination, as well as its applications to unsymmetrical N,N′-dialkylated phenylenediamines, was investigated. 相似文献
154.
Dr. Jin Su Dr. Tohru Tsuruoka Dr. Takuji Tsujita Dr. Yuu Inatomi Dr. Kazuya Terabe 《Angewandte Chemie (International ed. in English)》2023,62(9):e202217203
Solid-state batteries (SSBs) that use solid electrolytes instead of flammable liquid electrolytes have the potential to generate higher specific capacity and offer better safety. Magnesium (Mg) based SSBs with Mg metal anodes are considered to be one of the most promising energy storage candidates, because it gives high theoretical volumetric capacities of 3830 mAh cm−3. Here, we demonstrate an atomic layer deposition (ALD) process with a double nitrogen plasma process that successfully produces nitrogen-incorporated magnesium phosphorus oxynitride (MgPON) solid-state electrolyte (SSE) thin films at a low deposition temperature of 125 °C. The ALD MgPON SSEs exhibit an ionic conductivity of 0.36 and 1.2 μS cm−1 at 450 and 500 °C, respectively. The proposed ALD strategy shows the ability of conformal deposition nitrogen-doped SSEs on pattered substrates and is attractive for using nitride ion-conducing films as protective or wetting interlayers in solid-state Mg and Li batteries. 相似文献
155.
Capillary electrophoretic separation of 60 mer single-stranded DNA (ssDNA) and a single-base-substituted ssDNA was demonstrated using a size- and composition-controlled poly(ethylene glycol)-oligodeoxyribonucleotide block copolymer (PEG-b-ODN) as an affinity ligand. Under appropriate conditions, PEG-b-ODN and ssDNA with a complementary sequence formed a reversible complex via hybridization during the electrophoresis, while the copolymer did not interact with the single-base-substituted ssDNA. The copolymer's PEG length determined the electrophoretic mobility of the ssDNA; upon formation of the complex, the electrically neutral PEG added hydrodynamic friction to ssDNA. Simultaneously using two types of PEG-b-ODN copolymers whose PEG segments were of different lengths, we achieved the complete separation of the 60 mer ssDNA, its single-base-substituted ssDNA, and impurities. This method was sensitive enough to quantify a slight amount (approximately 1%) of the single-base-substituted ssDNA. The present results suggest that our approach is applicable to quantitative detection of minor genotypes. 相似文献
156.
Shoma Mizutani Kenta Komori Tohru Taniguchi Kenji Monde Kouji Kuramochi Kazunori Tsubaki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(33):9705-9708
A biomimetic synthesis of naturally occurring lactams rubrobramide, flavipucine, and isoflavipucine is described. The key step is a regioselective Darzens reaction between isobutyl glyoxal and an α‐bromo‐β‐ketoamide. The construction of the core tricyclic ring system of rubrobramide was achieved by a cascade reaction in a single step from an α,β‐epoxy‐γ‐lactam. Furthermore, the absolute configuration of naturally occurring (+)‐rubrobramide was determined by vibrational circular dichroism. (±)‐Flavipucine and (±)‐isoflavipucine were synthesized from an epoxyimide, which was prepared by reaction of isobutyl glyoxal with a protected α‐bromo‐β‐ketoamide. Deprotection of the epoxyimide and formation of the pyridone ring gave (±)‐flavipucine, which was converted into (±)‐isoflavipucine by thermal isomerization. 相似文献
157.
We study the global Cauchy problem for the mass critical nonlinear Schrödinger equations. We prove the global existence of analytic solutions in both space and time variables for sufficiently small and exponentially decaying Cauchy data. The method of proof depends on the Leibniz rule for the generator of pseudo-conformal transforms at the L 2 critical level. 相似文献
158.
Based on an amphotericin B (AmB) ion-channel model where the close proximity of neighboring molecules is effected by interaction between carboxyl and amino groups, we prepared covalent dimers of AmB connected between these functionalities. While directly connected and short-tethered derivatives (2 and 3) lacked the activities, dimer 4 with a longer linker revealed K+ ion flux activity, suggesting that some distance and/or flexibility between the carboxyl and amino groups in adjacent molecules is required for the formation of ion-permeable complex in biomembranes. 相似文献
159.
Eshima Nobuoki; Kohda Tohru; Tabata Minoru 《IMA Journal of Mathematical Control and Information》2007,24(3):289-298
160.
Kiyoshi Tanaka Tohru Kurushima Satoru Iwata Syunsuke Shimada 《Journal of heterocyclic chemistry》2007,44(2):303-307