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141.
Akio Saito Manabu Tojo Hikaru Yanai Fukiko Wada Muga Nakagawa Midori Okada Azusa Sato Rieko Okatani Takeo Taguchi 《Journal of fluorine chemistry》2012
CrCl2/Mn-mediated transformation of various dibromofluoromethylcarbinyl esters including carboxylates, carbonates and carbamates provided 1-fluoro-1-alkenyl esters via [2,3]-sigmatropic rearrangement of ester group. Reaction proceeded by using CrCl2/Mn system under mild conditions (in THF at room temperature) to give 1-fluoro-1-alkenyl esters in good yield with an excellent Z selective manner. 1-Fluoro-1-alkenyl ester thus obtained acts as a double acyl donor in the reaction with necleophiles such as amine, thiol, alcohol as well as bifunctional necleophiles such as ethylene diamine derivative. 相似文献
142.
Kanno M Nakamura K Kanai E Hoki K Kono H Tanaka M 《The journal of physical chemistry. A》2012,116(9):2177-2183
There have been a growing number of articles that report dramatic improvements in the experimental performance of chemical reactions by microwave irradiation compared to that under conventional heating conditions. We theoretically examined whether nonthermal microwave effects on intramolecular reactions exist or not, in particular, on Newman-Kwart rearrangements and intramolecular Diels-Alder reactions. The reaction rates of the former calculated by the transition state theory, which consider only the thermal effects of microwaves, agree quantitatively with experimental data, and thus, the increases in reaction rates can be ascribed to dielectric heating of the solvent by microwaves. In contrast, for the latter, the temperature dependence of reaction rates can be explained qualitatively by thermal effects but the possibility of nonthermal effects still remains regardless of whether competitive processes are present or not. The effective intramolecular potential energy surface in the presence of a microwave field suggests that nonthermal effects arising from potential distortion are vanishingly small in intramolecular reactions. It is useful in the elucidation of the reaction mechanisms of microwave synthesis to apply the present theoretical approach with reference to the experiments where thermal and nonthermal effects are separated by screening microwave fields. 相似文献
143.
Manabu Shilai Masanobu Uchiyama Yoshinori Kondo Takao Sakamoto 《Journal of heterocyclic chemistry》2001,38(2):481-484
Tellurium‐metal exchange reaction of n‐butyl 2‐pyridinyl telluride derivatives with n‐butyllithium or dilithium dimethylcyanocuprate proceeded smoothly to give the corresponding 2‐pyridinylmetal derivatives, which are important intermediates for functionalization of pyridines. 相似文献
144.
145.
Steven T. Dougherty T. Aaron. Gulliver Manabu Oura 《Designs, Codes and Cryptography》2006,38(1):97-112
We study higher weights applied to ternary and quaternary self-dual codes. We give lower bounds on the second higher weight
and compute the second higher weights for optimal codes of length less than 24. We relate the joint weight enumerator with
the higher weight enumerator and use this relationship to produce Gleason theorems. Graded rings of the higher weight enumerators
are also determined.
This work was supported in part by Northern Advancement Center for Science & Technology and the Natural Sciences and Engineering
Research Council of Canada. 相似文献
146.
Takahide Oya Yoshiyuki Takahashi Masayuki Ikebe Tetsuya Asai Yoshihito Amemiya 《Superlattices and Microstructures》2003,34(3-6):253
A single-electron circuit can be operated as a discrete dynamical system because it changes its internal state discontinuously because of electron tunneling. To confirm this idea, we designed a sample circuit for discrete dynamical operation and confirmed by computer simulation that the circuit successfully generated a sequence of discrete-time outputs by following a return map. The concept of discrete dynamical systems will be useful in developing new functional systems that consist of quantum devices and nanostructures. 相似文献
147.
148.
Akira Mori Kanji Kubo Manabu Takemoto Hayato Kitaura Seiji Ujiie 《Liquid crystals》2006,33(5):521-530
Two types of symmetric dimers with 5-(4-alkoxybenzoyloxy)tropone cores or with 4-(4-alkoxybenzoyloxy)phenyl cores were synthesized to evaluate the effect of the core structure and the length of the spacer on the mesomorphic properties. The former had smectic C phases whereas the latter had smectic C and F phases. Both types of dimer showed a remarkable odd-even effect on varying the spacer on the mesomorphic properties. Comparison of the thermal stability between them demonstrated that benzenoid twins are more stable than troponoid ones. The layer spacings of the smectic C phases were measured to determine the tilt angles of the core part, the spacer, and the side chains on changing the length of the spacer and the side chains. Troponoid dimers had a larger tilt angle of the core part of the smectic C phase than benzenoid twins, which lowered the thermal stability of the troponoid. Entropy changes of the smectic C phase to the isotropic liquid showed a contrast between troponoids and benzenoids. The former had smaller values and odd-even effects than the latter, which indicated that the former troponoids had a limited number of conformers in mesophases. 相似文献
149.
Manabu Oura 《Discrete Mathematics》2008,308(16):3722-3725
It is known that the weight enumerator of a self-dual doubly even code in genus g=1 can be uniquely written as an isobaric polynomial in certain homogeneous polynomials with integral coefficients. We settle the case where g=2 and prove the non-existence of such polynomials under some conditions. 相似文献