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排序方式: 共有380条查询结果,搜索用时 187 毫秒
91.
92.
Toshio Kinoshita Tomoko Okunaka Takehiro Ohwada Hiroyuki Kawanaka Sunao Furukawa 《Journal of heterocyclic chemistry》1991,28(8):1901-1909
The following bromo-2,4(1H,3H)-pyrimidinediones possessing a bromo substituent at the 5-position and side chains at the 1- and 6-positions were prepared. The three types of mono-bromo derivatives are: 1-(bromoalkyl)-3,6-dimethyl- 3a-d , 5-bromo-3,6-dimethyl-1-(hydroxyalkyl)- 4a-d , and 1-(acetoxyalkyl)-5-bromo-3,6-dimethyl-2,4(1H,3H)-pyrimidinediones 11a-d . The three types of dibromo derivatives are: 5-bromo-1-(bromoalkyl)-3,6-dimethyl- Sa-d , 1-(acetoxyalkyl)-5-bromo-6-bromomethyl- 8a, 8c , and 8d , and 5-bromo-6-bromomethyl 1-(hydroxyalkyl)-2,4(1H,3H)-pyrimidinediones 9a, 9c , and 9d . Likewise one group of tribromo and one group of tetrabromo derivatives are: 5-bromo-1-(bromoalkyl)-6-bromomethyl -7a-d and 5-bromo-1-(bromoalkyl)-6-dibromomethyl-2,4(1H,3H)-pyrimidinediones 6a-d . 相似文献
93.
Yasuyuki Takeda Takehiro Iwasaki Yoshihiro Kudo Hiroaki Matsuda 《Journal of inclusion phenomena and macrocyclic chemistry》1992,14(3-4):303-309
Thermodynamic parameters (H
ex
0
and S
ex
0
) for the overall extractions of monovalent metal (Na, K, Rb, and Tl) picrates with benzo-18-crown-6 (B18C6), and those (H
D,L
0
and S
D,L
0
) for the distribution of B18C6 were determined between chloroform and water. All the extracted B18C6 complexes were l:1:1 complexes (B18C6:metal ion: picrate anion). The H
ex
0
and S
ex
0
values for all the metals are negative. Every extraction of the metal picrate with B18C6 is completely enthalpy driven. The H
D,L
0
and S
D,L
0
values of B18C6 are both positive, and the partition of B18C6 is entirely entropy driven. Enthalpy (H
ex,ip
0
) and entropy changes (S
ex,ip
0
) for ion-pair extractions of B18C6-metal ion complexes with picrate anions were calculated. All the H
ex,ip
0
and S
ex,ip
0
values are negative, and the ion-pair extractions are completely enthalpy driven. 相似文献
94.
Immobilization of sunflower trypsin inhibitor (SFTI-1) peptide onto a gold surface and analysis of its interaction with trypsin 总被引:1,自引:0,他引:1
Sunflower trypsin inhibitor (SFTI-1) derived peptide having one disulfide bond could be immobilized via a thiol-disulfide exchange reaction onto a gold surface on a quartz crystal microbalance (QCM) chip. This permitted quantitative analysis of the specific interaction with trypsin. 相似文献
95.
Yoshihiro Ushigoe Shogo Tanaka Masatomo Nojima Kevin J. McCullough 《Tetrahedron letters》1994,35(52):9741-9744
-Hydroperoxyisochroman derivatives 5 react with formaldehyde under acidic conditions to produce mixtures of bicyclic 1,2,4,6-tetroxepane 9 and 1,2,4,6,8-pentoxonane 10 derivatives. The structure of the compound 10a was unambiguously established by the X-ray analysis. With acetaldehyde, only the corresponding 1,2,4,6-tetroxepanes 9 were obtained. 相似文献
96.
Hirobumi Takahashi Takehiro Fukami Hisaki Kojima Takeru Yamakawa Hiroyuki Takahashi Toshihiro Sakamoto Teruyuki Nishimura Masayuki Nakamura Takashi Yosizumi Kenji Niiyama Norikazu Ohtake Takashi Hayama 《Tetrahedron》2005,61(14):3473-3481
A robust synthetic method for 2-alkylamino-6-carboxy-5,7-diarylcyclopenteno[1,2-b]pyridines via acylamination at the alpha position of the functionalized pyridine system has been developed. The key step in this method was achieved by treatment of the corresponding pyridine N-oxides with 2.5 equiv of imidoyl chlorides in the presence of triethylamine, thus producing the desired 2-acylaminopyridines in good yields (74-96%). 相似文献
97.
Hiroshi Moriwaki Masanori Okabayashi Takehiro Watanabe Hideya Kawasaki Ryuichi Arakawa 《Rapid communications in mass spectrometry : RCM》2009,23(14):2161-2166
Zinc pyrithione (ZnPT) is widely used as an antidandruff or antifouling reagent. However, this compound is considered toxic, such as the teratogenic effect, to aquatic lives, and it is important to clarify the mechanism of its toxicity. In this study, the interactions between ZnPT and amino acids were observed using electrospray ionization mass spectrometry (ESI‐MS) in order to obtain information on the activity of ZnPT within the living body. The ZnPT complex ([ZnPT‐ligand+Amino acid]+), in which the ligand of ZnPT was exchanged by the amino acid, was detected in ZnPT solutions mixed with one of 20 amino acids by ESI‐MS. Histidine and cysteine, in particular, showed a high reactivity with ZnPT, while serine and glycine showed a low reactivity. The complexes of ZnPT and a peptide were also observed by the ESI‐MS measurement of the solution containing ZnPT with the peptide. These results would be useful to understand the mechanism of ZnPT toxicities to living creatures. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
98.
In this paper, incorporating a social psychological aspect of decision making, called attitudes, into analysis of games in normal form, the author proposes a new equilibrium concept, called relational dominant strategy equilibrium (RDSE). The author also analyzes relationships between RDSE and dominant strategy equilibrium (DSE), and shows the following fact: RDSE coincides with DSE under a condition on attitudes of players. The story of “The Gift of the Magi” by Henry is analyzed and given a convincing interpretation using the proposed equilibrium concept. 相似文献
99.
The structure of the Co thin films on Pd(1 1 1) and the effect of the CO adsorption on Co thin films were studied by Co K-edge surface X-ray absorption fine structure (XAFS). The polarization dependences of the X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra indicate that Co thin films grow in the fcc stacking mode on Pd(1 1 1) up to 12 ML. The analysis of the nearest neighbor shell shows little mechanical strain at the interface, indicating that Co atom does not grow pseudomorphically on Pd(1 1 1). There is no alloy-like structure at the interface. CO adsorption causes no structural change of the Co thin films but modifies the Co surface electronic state. These structural studies provide deep insight in the magnetic property of the Co thin films on Pd(1 1 1). 相似文献
100.
A simple method for the determination of the absolute configuration of 1-arylethanthiols was achieved by the observation of an intramolecular CH/pi shielding effect in (1)H-NMR of the corresponding thiol esters. (S)-Isomer of the diastereomers always shows remarkable shielding effect. 相似文献