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161.
Anisotropic Expansion of an M2L4 Coordination Capsule: Host Capability and Frame Rearrangement
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Masahiro Yamashina Tsubasa Yuki Dr. Yoshihisa Sei Prof. Dr. Munetaka Akita Dr. Michito Yoshizawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(11):4200-4204
Anisotropic expansion of a spherical M2L4 coordination capsule through the elongation of the ligand led to a new M2L′4 capsule. The expanded capsule provides an elliptical cavity encircled by polyaromatic frameworks with large openings and thereby can encapsulate elliptical fullerene C70 and monofunctionalized fullerene C60 in high yields. In addition, selective formation of a new M2L2L′2 capsule occurs by mixing the original M2L4 and expanded M2L′4 capsules in a 1:1 ratio upon addition of C60 or monofunctionalized C60 as a template molecule. 相似文献
162.
Carboxylations of alkali metal phenoxides with carbon dioxide 总被引:1,自引:0,他引:1
Kosugi Y Imaoka Y Gotoh F Rahim MA Matsui Y Sakanishi K 《Organic & biomolecular chemistry》2003,1(5):817-821
The reaction mechanism of the Kolbe-Schmitt reaction of phenol and 2-naphthol has been investigated. An alkali metal phenoxide-CO2 complex is not an intermediate that can be easily transformed into a carboxylic acid, such as salicylic acid (SA) and p-hydroxybenzoic acid (pHBA). A direct carboxylation of phenoxide with CO2 takes place even at room temperature, and is competitive with the formation of the CO2 complex. The resulting complex decomposes thermally (above ca. 100 degrees C) to phenoxide, which then undergoes further competitive reactions. Experiments using a carbon-13 labeled complex support a mechanism of direct carboxylation, and not the mechanism via a CO2 complex. The reactivity, C-13 NMR and MOPAC/PM3 calculations suggest a new carbonate-like structure for the CO2 complex. 相似文献
163.
Shuichi Jimbo Yoshihisa Morita 《Calculus of Variations and Partial Differential Equations》2002,15(3):325-352
We study the Ginzburg-Landau equation with magnetic effect in a thin domain in , where the thickness of the domain is controlled by a parameter . This equation is an Euler equation of a free energy functional and it has trivial solutions that are minimizers of the functional.
In this article we look for a nontrivial stable solution to the equation, that is, a local minimizer of the energy functional.
To prove the existence of such a stable solution in , we consider a reduced problem as and a nondegenerate stable solution to the reduced equation. Applying the standard variational argument, we show that there
exists a stable solution in near the solution to the reduced equation if is sufficiently small. We also present a specific example of a domain which allows a stable vortex solution, that is, a stable
solution with zeros.
Received: 11 May 2001 / Accepted: 11 July 2001 /Published online: 19 October 2001 相似文献
164.
Yunyan Gao Maki inoue Takehiko Wada Yoshihisa Inoue 《Journal of inclusion phenomena and macrocyclic chemistry》2004,50(1-2):111-114
Supramolecular enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to chiral (E)-isomer (1E) through inclusion and sensitization by 6-O-mono(o-methoxybenzoyl)--cyclodextrin (2) was investigated in water and in aqueous methanol solutions at various temperatures. A dramatic inversion of the product chirality was observed to occur by simply changing the solvent from water to methanol. Thus, the supramolecular photosensitization in aqueous solution gave (R)-(–)-1E in 15% enantiomeric excess (ee), whereas in methanol the antipodal (S)-(+)-1E was obtained in 5% ee. The temperature and solvent dependencies of the product ee are discussed. 相似文献
165.
Yoshihisa Kurasawa Muneto Muramatsu Keizo Hotehama Yoshihisa Okamoto Atsushi Takada 《Journal of heterocyclic chemistry》1985,22(6):1711-1712
The reactions of 3-methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline 1 with aryl diazonium salts gave 3-(α-aryldiazenylmethoxycarbonylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines 2a-c , whose reactions with hydrazine hydrate afforded 3-(α-aryldiazenylhydrazinocarbonylmethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines 3a-c . The reactions of 3a-c with nitrous acid resulted in the Curtius rearrangement to provide the 1-aryl-3-quinoxalinyl-1,2,4-triazol-5-ones 4a-c. 相似文献
166.
[structure: see text] Using chiral auxiliaries, 2-methoxy-2-(1-naphthyl)propionic acid (MalphaNP acid) (S)-(+)-1 and its deuterium-labeled enantiomer (R)-(-)-1-d(n)() (n = 3 or 6), we have developed a new diastereomer method for determining enantiomeric excess (% ee) of chiral alcohols by (1)H NMR and/or MS spectrometry, where the kinetic resolution effect is completely excluded. The data of % ee determined by this method agree well with those calculated by weight, the average error being ca. +/-1.08% ee. 相似文献
167.
Shi-Wei Zhang Take-aki Mitsudo Teruyuki Kondo Yoshihisa Watanabe 《Journal of organometallic chemistry》1993,450(1-2):197-207
Allylic carbonates except for allyl methyl carbonate reacted with carbonucleophiles such as ethyl acetoacetate in the presence of a catalytic amount of Ru(cod)(cot) [cod = cycloocta-1,5-diene, COT = cycloocta-1,3,5-triene] in N-methylpiperidine at 80°C to give the corresponding monoallylated carbonucleophiles in high yields with high regioselectivity. The regioselectivity was quite different from that in the palladium-catalyzed reactions. The allylation of carbonucleophiles using allyl methyl carbonate selectively gave the diallylated carbonucleophiles in high yields. 相似文献
168.
Yoshihisa Kurasawa Kaoru Yamazaki Setsuko Tajima Yoshihisa Okamoto Atsushi Takada 《Journal of heterocyclic chemistry》1986,23(3):957-958
3-Formyl-2-oxo-1,2-dihydroquinoxaline chlorophenylhydrazones 4a-c were synthesized from the reactions of 3-methyl-2-oxo-1,2-dihydroquinoxaline 3 with chlorophenyl diazonium salts, and 4b,c were found to exhibit the tautomeric equilibria between the hydrazone imine and diazenyl enamine forms in the dimethylsulfoxide solutions. 相似文献
169.
Ho Sik Kim Tong Eun Kim Sam Tag Kwag Yong Tae Park Young Seuk Hong Yoshihisa Okamoto Yoshihisa Kurasawa 《Journal of heterocyclic chemistry》1997,34(5):1539-1542
The reaction of the 6-chloro-2-(1-methyl-2-thiocarbamoylhydrazino)quinoxaline 4-oxides 3a-d with trifluoroacetic anhydride gave the 2-(N-aryl)trifluoroacetamido-8-chloro-4-methyl-4H-1,3,4-thiadiazino-[5,6-b]quinoxalines 7a-d , respectively, while the reflux of compounds 3a-c in N,N-dimethylformamide afforded the mesoionic triazolo[4,3-a]quinoxaline 4 . Hydrolysis of compounds 7a-d with triethylamine/water provided the 2-arylamino-8-chloro-4-methyl-4H-1,3,4-thiadiazino[5,6-b)]quinoxalines 8a-d , respectively. 相似文献
170.
The 13C NMR behaviors of several cyclic and biaryl secondary alcohols as well as acyclic tertiary alcohols have been studied in the chiral bidentate NMR solvent BMBA-p-Me (1). An empirical rule has been advanced to correlate the absolute configuration of each type of alcohols with the 13C chemical shift behaviors in (R,R)- and (S,S)-BMBA-p-Me. 相似文献