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131.
Sumimoto M Kawashima Y Hori K Fujimoto H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(1):286-287
A recent paper by Lui et al. [Z. Liu, X. Zhang, Y. Zhang, J. Jiang, Spectrochim. Acta A 67 (2007) 1232] reported on the theoretical investigations of the fully optimized geometries and electronic structures of iron (II) phthalocyanine (FePc) with the singlet spin state carried out with the restricted density functional theory (DFT) method, where the B3LYP functional was adopted for the exchange-correlation term; however, the triplet spin state was experimentally reported, and we also obtained the triplet spin state by the unrestricted DFT calculations. 相似文献
132.
Dr. Ismail Hamdi Dr. Guy Buntinx Dr. Amit Kumar Tiwari Dr. Stéphanie Delbaere Dr. Michinori Takeshita Dr. Stéphane Aloïse 《Chemphyschem》2020,21(19):2223-2229
Time-resolved absorption spectroscopy measurements were performed to study the dynamics of photochromic 1,2-Bis(2,4-dimethylthiophene-3-yl)perfluoro-cyclopentene (DMTPF) in chloroform, including antiparallel conformer ring-closure reaction and parallel conformer photophysics. All characteristic times are given, discussed and compared to a previous publication concerning the close molecule substituted with phenyl rings. (Hamdi et al., PCCP, 2016). Apart from the expected photocyclization process, condensed ring by-product formation is observed and hypotheses concerning the origin of this by-product are presented. 相似文献
133.
134.
Oki M 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2010,86(9):867-883
Isolation of rotational isomer models of ethane-type molecules is described. We could experimentally prove that, if rotational isomers whose molecular shape was chiral, the molecule could be optically active, even though it did not carry an asymmetric carbon atom. As an extension, other types of stereochemically fundamental and optically active molecules were isolated and their absolute stereochemistry was determined. One example is the model of meso-tartaric acid, for which optical inactivity had been attributed to internal compensation but is now explained as follows. On dissolution of meso-tartaric acid in a solvent, the molecule gives two kinds of conformers, one of which is a C(i) molecule and the other is a C(1) molecule. Although the latter is intrinsically optically active, the optical activity is cancelled by its enantiomer. The theory of internal compensation is recommended to be abandoned. As an extension to another area, some reactions of conformers are also discussed. 相似文献
135.
136.
Jukiya Sakamoto Yuhei Umeda Kenta Rakumitsu Prof. Dr. Michinori Sumimoto Prof. Dr. Hayato Ishikawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13516-13524
A collective synthesis of glycosylated monoterpenoid indole alkaloids is reported. A highly diastereoselective Pictet–Spengler reaction with α-cyanotryptamine and secologanin tetraacetate as substrates, followed by a reductive decyanation reaction, was developed for the synthesis of (−)-strictosidine, which is an important intermediate in biosynthesis. This two-step chemical method was established as an alternative to the biosynthetically employed strictosidine synthase. Furthermore, after carrying out chemical and computational studies, a transition state for induction of diastereoselectivity in our newly discovered Pictet–Spengler reaction is proposed. Having achieved the first enantioselective total synthesis of (−)-strictosidine in just 10 steps, subsequent bioinspired transformations resulted in the concise total syntheses of (−)-strictosamide, (−)-neonaucleoside A, (−)-cymoside, and (−)-3α-dihydrocadambine. 相似文献
137.
138.
Collective Synthesis and Biological Evaluation of Tryptophan‐Based Dimeric Diketopiperazine Alkaloids 下载免费PDF全文
Shinji Tadano Yukihiro Sugimachi Prof. Dr. Michinori Sumimoto Prof. Dr. Sachiko Tsukamoto Prof. Dr. Hayato Ishikawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(4):1277-1291
A concise two one‐pot synthesis of WIN 64821, eurocristatine, 15,15′‐bis‐epi‐eurocristatine, ditryptophenaline, ditryptoleucine A, WIN 64745, cristatumin C, asperdimin, naseseazine A, and naseseazine B is detailed, based on a unique bioinspired dimerization reaction of tryptophan derivatives in aqueous acidic solution and a one‐pot procedure for the construction of diketopiperazine rings. Total yields of these alkaloid syntheses were from 10 up to 27 %. In addition, 1′‐(2‐phenylethylene)‐ditryptophenaline was synthesized by using three one‐pot operations. The studies detailed herein provided synthesized natural products for inhibitory activities of ubiquitin‐specific protease 7 (USP7) and foam cell formation in macrophages. The newly listed biological evaluation for tryptophan‐based dimeric diketopiperazine alkaloids discovered 15,15′‐bis‐epi‐eurocristatine, 1′‐(2‐phenylethylene)‐ditryptophenaline, and WIN 64745 as new drug candidates. 相似文献
139.
Three‐Way‐Switchable (Right/Left/OFF) Selective Reflection of Circularly Polarized Light on Solid Thin Films of Helical Polymer Blends 下载免费PDF全文
Dr. Yuuya Nagata Makoto Uno Prof. Dr. Michinori Suginome 《Angewandte Chemie (International ed. in English)》2016,55(25):7126-7130
Two poly(quinoxaline‐2,3‐diyl) copolymers bearing miscibility‐enhancing 8‐chlorooctyloxy and (S)‐2‐methylbutoxy or n‐butoxy side chains were synthesized. After annealing in CHCl3 vapor, a polymer‐blend film of these copolymers exhibited selective reflection of right‐handed circularly polarized light (CPL) in the visible region. The handedness of the CPL reflected was completely inverted upon annealing of the film in THF vapor. Annealing in n‐hexane vapor resulted in the phase separation of the polymer blend, which turned the selective reflection off. This three‐way‐switchable reflection, that is, reflection of right‐handed or left‐handed CPL, together with an OFF state, could be observed visually through right‐ and left‐handed CPL filters. 相似文献
140.
Redox Switching of Orthoquinone‐Containing Aromatic Compounds with Hydrogen and Oxygen Gas 下载免费PDF全文
Kazuki Urakawa Prof. Dr. Michinori Sumimoto Prof. Dr. Mitsuhiro Arisawa Prof. Dr. Masaki Matsuda Prof. Dr. Hayato Ishikawa 《Angewandte Chemie (International ed. in English)》2016,55(26):7432-7436
Unique redox switching of orthoquinone‐containing pentacyclic aromatic compounds with molecular hydrogen and oxygen in the presence of a palladium nanoparticle catalyst (SAPd) is disclosed. These molecules were predicted by in silico screening before synthesis. Efficient protocols for the synthesis of orthoquinone‐containing aromatic compounds by palladium‐mediated homocoupling and the benzoin condensation reaction were developed. Clear switching between orthoquinone and aromatic hydroquinone compounds was observed on the basis of their photoluminescence properties. Furthermore, the twist strain of the orthoquinone moiety could induce dramatic changes in color and emission. 相似文献