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61.
Cationic iron(III) porphyrin was found to be an efficient catalyst for the highly chemoselective hetero-Diels-Alder-type reaction of aldehydes with 1,3-dienes. The catalyzed process did not require the use of electron-deficient aldehydes such as glyoxylic acid derivatives or activated electron-rich 1,3-dienes such as Danishefsky's diene and Rawal's diene. The high functional group tolerance and robustness of the catalyst were demonstrated. Further, the potential utility of the catalyst was demonstrated by performing the cycloaddition in the presence of water and by carrying out cycloaddition of an unactivated ketone such as cyclohexanone with a diene. 相似文献
62.
We disclose a new planarized triarylborane in which the tri-coordinated boron atom is embedded in a fully fused polycyclic π-conjugated skeleton. The compound shows high stability toward oxygen, water, and silica gel, despite the absence of steric protection around the B atom. Reflecting the electron-donating character of the π-skeleton and the electron-accepting character of the B atom, this compound shows broad absorption bands that cover the entire visible region and a fluorescence in the visible/near-IR region. In addition, this compound shows dramatic property changes upon formation of a tetra-coordinated borate, such as thermochromic behavior in the presence of pyridine. 相似文献
63.
Rui Umeda Masahito Muraki Yuudai Nakamura Tomoyuki Tanaka Kyohei Kamiguchi Yutaka Nishiyama 《Tetrahedron letters》2017,58(24):2393-2395
The Meinwald rearrangement reaction of oxiranes to the corresponding carbonyl compounds is efficiently catalyzed by the ReBr(CO)5 complex. 相似文献
64.
Y Watanabe H Usui T Shibano T Tanaka M Kanao 《Chemical & pharmaceutical bulletin》1990,38(10):2726-2732
New serotonine 2 (5-HT2) antagonists with a monocyclic or bicyclic 2,4(1H,3H)-pyrimidinedione have been prepared and their activities evaluated. In a series of monocyclic compounds, 1-substituted 5-phenyl-2,4(1H,3H)-pyrimidinedione 14 showed potent in vitro activity, and the corresponding 3-substituted 5-phenyl and 6-phenyl derivatives 3, 8 and 20a also showed moderate activity. In the bicyclic compounds, 3-substituted 5,6,7,8-tetrahydro-2,4(1H,3H)-quinazolinedione 33 exhibited the most potent activity among the compounds prepared in this paper. The in vivo antagonist activity of 33 was comparable to that of ketanserin, a typical peripheral 5-HT2 antagonist. 相似文献
65.
Cover Picture: Asymmetric Induction by a Nitrogen 14N/15N Isotopomer in Conjunction with Asymmetric Autocatalysis (Angew. Chem. Int. Ed. 49/2016)
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66.
Taniguchi M Yokota O Shibano M Wang NH Baba K 《Chemical & pharmaceutical bulletin》2005,53(6):701-704
Four new coumarins (1-4) were isolated from the roots of Heracleum yunngningense HAND.-MASS. Their structures were established by spectral analyses. 相似文献
67.
68.
Intermolecular Arrangement of Fullerene Acceptors Proximal to Semiconducting Polymers in Mixed Bulk Heterojunctions
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Dr. Chao Wang Dr. Kyohei Nakano Dr. Hsiao Fang Lee Yujiao Chen Dr. You‐Lee Hong Dr. Yusuke Nishiyama Dr. Keisuke Tajima 《Angewandte Chemie (International ed. in English)》2018,57(24):7034-7039
Precise control of the molecular arrangements at the interface between the electron donor and acceptor in mixed bulk heterojunctions (BHJs) remains challenging, despite the correlation between structural characteristics and efficiency in organic photovoltaics (OPVs). This study reveals that the substitution patterns of linear and branched alkyl side chains on electron‐donating/‐accepting alternating copolymers can control the positions of an acceptor molecule (C60) around the π‐conjugated main chains in mixed BHJs. Two‐dimensional solid‐state NMR demonstrates a marked difference in the location of C60 in the blend films. A copolymer with an electron‐accepting unit positioned in close proximity to C60 demonstrated higher OPV performance in combination with various fullerene derivatives. This molecular design offers precise control over the interfacial molecular structure, thereby paving the way for overcoming the current limitations of OPVs comprising mixed BHJs. 相似文献
69.
Peni Ahmadi Kyohei Muguruma Tsung-Che Chang Satoru Tamura Kazuki Tsubokura Yasuko Egawa Takehiro Suzuki Naoshi Dohmae Yoichi Nakao Katsunori Tanaka 《Chemical science》2021,12(37):12266
Selective cell tagging (SeCT) therapy is a strategy for labeling a targeted cell with certain chemical moieties via a catalytic chemical transformation in order to elicit a therapeutic effect. Herein, we report a cancer therapy based on targeted cell surface tagging with proapoptotic peptides (Ac-GGKLFG-X; X = reactive group) that induce apoptosis when attached to the cell surface. Using either Au-catalyzed amidation or Ru-catalyzed alkylation, these proapoptotic peptides showed excellent therapeutic effects both in vitro and in vivo. In particular, co-treatment with proapoptotic peptide and the carrier–Ru complex significantly and synergistically inhibited tumor growth and prolonged survival rate of tumor-bearing mice after only a single injection. This is the first report of Ru catalyst application in vivo, and this approach could be used in SeCT for cancer therapy.The combination of a proapoptotic peptide with covalent tagging and a carrier-Ru-complex inhibited tumor growth in mice after a single injection. 相似文献
70.
Dr. Moulali Vaddamanu Dr. Arruri Sathyanarayana Yamane Masaya Shohei Sugiyama Ozaki Kazuhisa Dr. Kavitha Velappan Muneshwar Nandeshwar Dr. Kyohei Hisano Osamu Tsutsumi Prof. Dr. Ganesan Prabusankar 《化学:亚洲杂志》2021,16(5):521-529
The synthesis and the luminescence features of three gold(I)-N-heterocyclic carbene (NHC) complexes are presented to study how the n-alkyl group can influence the luminescence properties in the crystalline state. The mononuclear gold(I)-NHC complexes, [( L1 )Au(Cl)] ( 1 ), [( L2 )Au(Cl)] ( 2 ), and [( L3 )Au(Cl)] ( 3 ) were isolated from the reactions between [(tht)AuCl] and corresponding NHC ligand precursors, [N-(9-acridinyl)-N’-(n-butyl)-imidazolium chloride, ( L1 .HCl)], [N-(9-acridinyl)-N’-(n-pentyl)-imidazolium chloride, ( L2 .HCl)] and [N-(9-acridinyl)-N’-(n-hexyl)-imidazolium chloride, ( L3 .HCl)]. Their single-crystal X-ray analysis reveals the influence of the n-alkyl groups on solid-state packing. A comparison of the luminescence features of 1 – 3 with n-alkyl substituents is explored. The molecules 1 – 3 depicted blue emission in the solution state, while the yellow emission (for 1 ), greenish-yellow emission (for 2 ), and blue emission (for 3 ) in the crystalline phase. This paradigm emission shift arises from n-butyl to n-pentyl and n-hexyl in the crystalline state due to the carbon-carbon rotation of the n-alkyl group, which tends to promote unusual solid packing. Hence n-alkyl group adds a novel emission property in the crystalline state. Density Functional Theory and Time-Dependent Density Functional Theory calculations were carried out for monomeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride and dimeric complex, N-(9-acridinyl)-N’-(n-heptyl)imidazole-2-ylidene gold(I) chloride to understand the structural and electronic properties. 相似文献