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The synthetic process equivalent to C-unsubstituted (CH) nitrile ylides cycloaddition reaction is achieved via cycloaddition of NH-azomethine ylide and the following fission reaction of the cycloadducts under acidic conditions. Cycloaddition of NH-azomethine ylide generated by a thermal 1,2-prototropy in 4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carbaldehyde system with maleimides provides proline derivatives under extremely mild conditions. Heating their adducts in AcOH at 85 °C causes a cleavage of C-C bond between the proline and heterocyclic moiety to give the parent heterocyclic system and dehydroproline derivatives, which is regarded as a cycloadduct of C-unsubstituted (CH) nitrile ylide. This cycloaddition-fission reaction sequences can be applied to one-pot three-component reaction. 相似文献
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Shoji Kajigaeshi Shingo Matsuoka Shuji Kanemasa Michihiko Noguchi 《Journal of heterocyclic chemistry》1986,23(1):49-52
Tropone benzoyl- and tosylhydrazones underwent the [8+2] cycloaddition reaction with isocyanates to afford the cyclohepta[d]imidazolin-2-one derivatives. This means that these hydrazones behaved as 8-amino-8-azaheptafulvenes. Also, the tropone hydrazones reacted with phenylketene and phenylsulfene in more complicated manners. 相似文献
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Shu Karube Wataru HoshinoTatsuo Soutome Keijin Sato 《International Journal of Non》2002,37(3):541-564
It is well-known that vibration cutting is an effective method to cut materials with accuracy. However, it often suffers from unevenness of surface roughness caused by the non-linear vibration phenomena in tool-work vibration system. To solve this problem, we propose a vibration cutting model described by two-dimensional differential equations to analyze the non-linear phenomena. This non-linear model reproduces the basic features of the real vibration cutting systems, that is, the reduction of the cutting force and the displacement of work by pulsing of the cutting force. In this report, our experiment shows that various non-linear phenomena exist in the vibration cutting system. Our non-linear model for the vibration cutting produce behaviors which qualitatively agree with these various non-linear phenomena. These behaviors can be classified by the Lyapunov exponents. 相似文献
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Saira?Hameed Koji?Ikegami Eiji?Sugiyama Shoko?Matsushita Yoshishige?Kimura Takahiro?Hayasaka Yuki?Sugiura Noritaka?Masaki Michihiko?Waki Isao?Ohta Md?Amir?Hossen Mitsutoshi?SetouEmail author 《Analytical and bioanalytical chemistry》2015,407(25):7589-7602
A protocol for the direct analysis of the phospholipid composition in the whole body of adult soil nematode, Caenorhabditis elegans (C. elegans), was developed, which combined freeze-cracking of the exoskeletal cuticle and matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS). Biomolecules in the m/z range from 700 to 900 were more effectively detected in the freeze-cracked than from simple frozen adult nematode bodies. Different distribution of biomolecules was observed in a nematode body when the matrix was applied with a sublimation deposition method. The whole-body IMS technique was applied on genetically deficient mutant C. elegans to combine whole-body lipidomics and genetics, by comparing the fatty acid compositions, especially of the phosphatidylcholine (PC) species, between the wild-type and fat-1 mutants, which lack the gene encoding an n-3 fatty acid desaturase. A significant reduction of PC(20:5/20:5) and PC(20:4/20:5) and a marked increase of PC(20:4/20:4), PC(20:3/20:4), and PC(20:3/20:3) were detected in the fat-1 mutants in positive ion mode. In addition, phospholipid compositions other than PCs were analyzed in negative ion mode. A loss of a possible phosphatidylinositol (PI) with 18:0/20:5 and a compensative accumulation of putative PI(18:0/20:4) were detected in the fat-1 mutants. In conclusion, the whole-body MALDI-IMS technique is useful for the profiling of multiple biomolecules in C. elegans in both intra- and inter-individual levels. 相似文献
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Temperature‐Selective Dual Radical Generation from Alkyl Diiodide: Applications to Synthesis of Asymmetric CABC Multi‐Block Copolymers and Their Unique Assembly Structures 下载免费PDF全文
Jie Zheng Dr. Chen‐Gang Wang Yu Yamaguchi Michihiko Miyamoto Prof. Dr. Atsushi Goto 《Angewandte Chemie (International ed. in English)》2018,57(6):1552-1556
Temperature‐selective radical generation from a newly designed alkyl diiodide (I?R2?R1?I) was studied. R1?I and I?R2 had different reactivities for generating alkyl radicals in the presence of a tetraoctylammonium iodide (ONI) catalyst. Taking advantage of the temperature selectivity, we used the alkyl diiodide as a dual initiator in ONI‐catalyzed living radical polymerization to uniquely synthesize CABC non‐symmetric multi‐block copolymers. Because of their non‐symmetric structure, CABC multi‐block copolymers form unique assemblies, that is, Janus‐type particles with hetero‐segment coronas and flower‐like particles with hetero‐segment petals. 相似文献
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Teruaki Hayakawa Takashi Morishita Masaki Okazaki Mitsuru Ueda Kazuhiro Takeuchi Michihiko Asai 《Journal of polymer science. Part A, Polymer chemistry》2000,38(21):3875-3882
A convenient method for the synthesis of polyamides containing hydroxyl and amino substituents on the aromatic rings of the backbones was developed. These polymers were prepared readily by the chemoselective polycondensation of dicarboxylic acids with diamines with hydroxyl and amino functional groups via the activating agent diphenyl(2,3‐dihydro‐2‐thioxo‐3‐bezoxazolyl)phosphonate. The model reactions were studied in detail to demonstrate the feasibility of chemoselective polycondensation. The direct polycondensation of 5‐hydroxy or 5‐aminoisophthalic acid with 4,4′‐diamino‐4″‐hydroxytriphenylmethane proceeded smoothly under mild conditions and produced the desired polyamides with inherent viscosities up to 0.73 dL · g−1. The polymers obtained were characterized by IR, 1H NMR, and 13C NMR spectroscopies. The polymers were readily soluble in aprotic polar solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethyl formamide, and dimethyl sulfoxide. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3875–3882, 2000 相似文献
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We have studied current-driven dynamics of domain walls when an in-plane magnetic field is present in perpendicularly magnetized nanowires using an analytical model and micromagnetic simulations. We model an experimentally studied system, ultrathin magnetic nanowires with perpendicular anisotropy, where an effective in-plane magnetic field is developed when current is passed along the nanowire due to the Rashba-like spin-orbit coupling. Using a one-dimensional model of a domain wall together with micromagnetic simulations, we show that the existence of such in-plane magnetic fields can either lower or raise the threshold current needed to cause domain wall motion. In the presence of the in-plane field, the threshold current differs for positive and negative currents for a given wall chirality, and the wall motion becomes sensitive to out-of-plane magnetic fields. We show that large non-adiabatic spin torque can counteract the effect of the in-plane field. 相似文献
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Jeong SJ Inagaki M Higuchi R Miyamoto T Ono M Kuwano M Van Soest RW 《Chemical & pharmaceutical bulletin》2003,51(6):731-733
An antiangiogenic purine analog, 1,3-dimethylisoguaninium (1), was isolated from the ethanol (EtOH) extract of the Okinawan sponge Amphimedon paraviridis. The structure was elucidated on the basis of its spectral properties and X-ray crystallographic analysis. Compound 1 exhibited specific inhibition of the basic fibroblast growth factor (bFGF)-induced proliferation of bovine aorta endothelial cells (BAECs). Moreover, compound 1 reduced the tube formation of BAECs in a time-dependent manner. 相似文献