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191.
Total Synthesis of the 7,10‐Epimer of the Proposed Structure of Amphidinolide N,Part II: Synthesis of C17–C29 Subunit and Completion of the Synthesis
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Dr. Koji Ochiai Dr. Sankar Kuppusamy Yusuke Yasui Kenji Harada Dr. Nishant R. Gupta Dr. Yohei Takahashi Prof. Dr. Takaaki Kubota Prof. Dr. Jun'ichi Kobayashi Prof. Dr. Yujiro Hayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(10):3287-3291
The total synthesis of 7,10‐epimer of the proposed structure of amphidinolide N was accomplished. The requisite chiral C17–C29 subunit was assembled stereoselectively via Keck allylation, Shi epoxidation, diastereoselective 1,3‐reduction, and a later oxidative synthesis of the THF framework. The C1–C13 and C17–C29 subunits were successfully coupled using a Enders RAMP “linchpin” as the C14–C16 three carbon unit, thereby controlling the chirality at C14 and C16. The labile allyl epoxy moiety was successfully constructed by Grieco–Nishizawa olefination at a final stage of the synthesis. 相似文献
192.
Abstract Due to the wide use of polymers in medicine, researchers are required to solve a very important problem–to understand the interaction between materials of nonphysiological origin and the surrounding biological liquids, and tissues, particularly blood. 相似文献
193.
Life science and biology have advanced with the progress of microscope technology. A strong desire of life scientists is to
observe living cells with high spatial resolution. The development of soft x-ray microscopy using a special wavelength called
the water window started in the 1970s in order to fulfill this desire. However, the photon fluxes realized so far are still
insufficient for this application. Here, we review our work on a coherent water window x-ray generation based on high-order
harmonics driven by an infrared pulse. Our proposed generation scheme, combining an infrared laser driver and a neutral gas
medium, is efficient and scalable in output yields of the water window x-ray. 相似文献
194.
K. Hirose M. Ejima T. Fujibayashi Y. Fujii K. Futatsukawa O. Hashimoto T. Ishikawa S. Kameoka H. Kanda F. Kato S. Kinoshita T. Kinoshita T. Kon O. Konno K. Maeda A. Matsumura Y. Miura F. Miyahara H. Miyase T. Nakabayashi S.N. Nakamura H. Nomura K. Nonaka A. Ohtani Y. Okayasu M. Oyamada A. Sasaki H. Shimizu T. Takahashi T. Tamae H. Tamura T. Terasawa H. Tsubota K. Tsukada D. Uchida M. Ukai M. Wakamatsu T. Watanabe H. Yamauchi H. Yamazaki K. Yawata 《Physics letters. [Part B]》2009
195.
Mitsuji Yamashita Lakonda Nagaprasada Rao Valluru Krishna Reddy Motoki Maeda Tatsuo Oshikawa Masaki Takahashi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6-7):1661-1665
Novel pentofuranose analogs of phospha sugar derivatives were synthesized starting from 1-phenyl-2-phospholene 1-oxide ( 1 ). First, the allylic oxidation of 1-phenyl-2-phospholene 1-oxide ( 1 ) with CrO 3 in Ac 2 O-AcOH or 3-hydroxy-1-phenyl-2-phospholene ( 2 ) with MnO 2 afforded 1-phenyl-4-oxo-2-phospholene 1-oxide ( 3 ). The C-5 alkylation of 3 in the presence of NaH by using benzyl bromide or methyl iodide as electrophiles afforded the target title compounds. 相似文献
196.
Katsuyuki Ogura Kunio Sanada Kazumasa Takahashi Hirotada Iida 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):83-87
Abstract An efficient preparation of a 3-methylthio-2-alkanone (1) has been realized by the reaction of a 3-alkyl-2,4-pentanedione (8) with one mol-equiv of S-methyl methanethiosulfonate (4) in the presence of excess EtONa in EtOH. Furthermore, treatment of 8 with 4 and K2CO3 in refluxing acetone, followed by addition of MeOH and heating the resulting mixture, gave 1 in a high yield. These methods were applied to synthesis of pseudoionone. 相似文献
197.
Abstract In order to elucidate the initiation reaction of the photopolymerization with iron(III)-amine-carbon tetrachloride systems, the photochemical reaction process among iron(III), amine, and carbon tetrachloride in methanol solution was followed at 0°C by UV spectroscopy as for iron(III) ion. The rate constants of both the reduction of iron (III) under irradiation with light and the oxidation of iron(II) in the dark were measured, and were related to the rates of photopolymerization of methyl methacrylate. Kinetic study on the photopolymerization of methyl methacrylate with iron(III)-triethylenetetramine-carbon tetrachloride system was made in parallel in methanol solution at 0°C. The initiation mechanism of the photopolymerization was postulated. 相似文献
198.
Motohiro Akazome Toshiaki Takahashi Ryo-Ichi Sonobe Katsuyuki Ogura 《Supramolecular chemistry》2013,25(1):109-136
Abstract Crystallization of (R)-(1-naphthyl)glycyl-(R)-phenyl-glycine [(R,R)-1] in the presence of oligo(ethylene glycol) dimethyl ethers 2(n) or poly(ethylene glycol)s (PEGs, 3(Mn )) afforded inclusion compounds. The ratio of (R,R)-1/the guest polymer (2 or 3) was proportional to the length of the polymer chain. The crystal structure of a hepta(ethylene glycol) dimethyl ether-included compound was disclosed by X-ray crystallography which showed that (R,R)-1 molecules form a sheet and the guest molecule penetrates the crystal lattice of (R,R)-1 through a one-dimensional channel on the sheet. Powder X-ray analysis revealed that, regardless of the length of the guest polymer, the distance between the neighboring sheets remains unchanged (12.0–12.3 Å) in these inclusion crystals. By thermal analysis, it was shown that the decomposition points of these inclusion compounds became higher with the longer PEG included. The inclusion phenomenon enabled the fractionation of PEGs with various molecular weights, among which longer PEG was preferably included. 相似文献
199.
O. Takahashi Y. Masuda A. Muroya T. Furuya 《SAR and QSAR in environmental research》2013,24(5-6):547-558
In general, the docking scoring tends to have a size dependence related to the ranking of compounds. In this paper, we describe a novel method of parameter optimization for docking scores which reduce the size dependence and can efficiently discriminate active compounds from chemical databases. This method is based on a simplified theoretical model of docking scores which enables us to utilize large amounts of data of known active and inactive compounds for a particular target without requiring large computational resources or a complicated procedure. This method is useful for making scoring functions for the identification of novel scaffolds using the knowledge of active compounds for a particular target or a customized scoring function for an interesting family of drug targets. 相似文献
200.
Takahiro Egawa Kazuhisa Hirabayashi Dr. Yuichiro Koide Chiaki Kobayashi Dr. Naoya Takahashi Dr. Tomoko Mineno Dr. Takuya Terai Dr. Tasuku Ueno Dr. Toru Komatsu Dr. Yuji Ikegaya Prof. Norio Matsuki Prof. Tetsuo Nagano Dr. Kenjiro Hanaoka 《Angewandte Chemie (International ed. in English)》2013,52(14):3874-3877