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1.
Isamu Shiina Hiromi Oshiumi Minako Hashizume Yu-suke Yamai Ryoutarou Ibuka 《Tetrahedron letters》2004,45(3):543-547
A method for the synthesis of octalactin B is established via a new and quite effective mixed-anhydride lactonization for the synthesis of an eight-membered ring moiety using 2-methyl-6-nitrobenzoic anhydride with DMAP. Both an optically active linear precursor of the lactone and a side chain of octalactins are prepared by the enantioselective aldol reaction of ketene silyl acetals with aldehydes. 相似文献
2.
Kudoh T Fukuoka M Ichikawa S Murayama T Ogawa Y Hashii M Higashida H Kunerth S Weber K Guse AH Potter BV Matsuda A Shuto S 《Journal of the American Chemical Society》2005,127(24):8846-8855
We previously developed cyclic ADP-carbocyclic ribose (cADPcR, 2) as a stable mimic of cyclic ADP-ribose (cADPR, 1), a Ca(2+)-mobilizing second messenger. A series of the N1-ribose modified cADPcR analogues, designed as novel stable mimics of cADPR, which were the 2"-deoxy analogue 3, the 3"-deoxy analogue 4, the 3"-deoxy-2"-O-(methoxymethyl) analogue 5, the 3"-O-methyl analogue 6, the 2",3"-dideoxy analogue 7, and the 2",3"-dideoxydidehydro analogue 8, were successfully synthesized using the key intramolecular condensation reaction with phenylthiophosphate-type substrates. We investigated the conformations of these analogues and of cADPR and found that steric repulsion between both the adenine and N9-ribose moieties and between the adenine and N1-ribose moieties was a determinant of the conformation. The Ca(2+)-mobilizing effects were evaluated systematically using three different biological systems, i.e., sea urchin eggs, NG108-15 neuronal cells, and Jurkat T-lymphocytes. The relative potency of Ca(2+)-mobilization by these cADPR analogues varies depending on the cell-type used: e.g., 3"-deoxy-cADPcR (4) > cADPcR (2) > cADPR (1) in sea urchin eggs; cADPR (1) > cADPcR (2) approximately 3"-deoxy-cADPcR (4) in T-cells; and cADPcR (2) > cADPR (1) > 3"-deoxy-cADPcR (4) in neuronal cells, respectively. These indicated that the target proteins and/or the mechanism of action of cADPR in sea urchin eggs, T-cells, and neuronal cells are different. Thus, this study represents an entry to cell-type selective cADPR analogues, which can be used as biological tools and/or novel drug leads. 相似文献
3.
Itsuo Mori Yoshikazu Fujita Minako Toyoda Yoko Takeuchi 《Fresenius' Journal of Analytical Chemistry》1992,344(6):292-294
Summary A highly sensitive determination of osmium(VIII) is based on the decolouring reaction with pyrogallolphthalein (gallein) and hydrogen peroxide in the presence of Brij 35. Beer's law was obeyed in the range of 0–0.5 ng of osmium(VIII) per 10 ml and the apparent decomposed absorption coefficient was 2.5×109 l mol–1 cm–1 at 535 nm.Application of xanthene derivatives in analytical chemistry. Part XCIII. Part XCII see ref. [1] 相似文献
4.
Mariko Kitajima Minako Anbe Noriyuki Kogure Sumphan Wongseripipatana Hiromitsu Takayama 《Tetrahedron》2014
Seven new indole alkaloids (aspidofractinine type 1–3, kopsine type 5, strychnos type 6, and vincamine type 7, 8) were isolated from Kopsia jasminiflora (Apocynaceae) collected in Thailand. 5-Oxokopsinic acid (4) was isolated from nature for the first time. The structures of the new alkaloids were determined by spectroscopic analyses and chemical transformation of a known alkaloid. 5,6-Secokopsinine (1) possesses a dialdehyde function that is formed by oxidative cleavage of the C-5–C-6 bond of kopsinine (9). New vincamine-type alkaloid 8 showed potent inhibitory activity toward human cancer cell lines (A549, HT29, HCT116). 相似文献
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6.
Isamu Shiina Takashi Katoh Shunsuke Nagai Minako Hashizume 《Chemical record (New York, N.Y.)》2009,9(6):305-320
Various intermediates for the synthesis of erythronolide A, an aglycon of erythromycin A, are prepared from the corresponding seco‐acids using 2‐methyl‐6‐nitrobenzoic anhydride (MNBA) in the presence of 4‐(dimethylamino)pyridine (DMAP) with or without triethylamine. The efficiency of the MNBA lactonization is assessed by studying this method and comparing the results with those of the other established macrocyclization protocols. It has been finally concluded that (i) the conformationally appropriate substrate for the monomeric cyclization gave the desired lactone in excellent yield under mild reaction conditions in the presence of MNBA and DMAP, (ii) the highly‐strained substrate for the cyclization also afforded the monomeric lactone in relatively good yield at 100°C in toluene, and (iii) the seco‐acid having stable linear conformation, which preferred dimerizing more than forming the monomeric lactone, provided the corresponding diolide in high yield with the constant ratio of the monomer to dimeric lactone (approximately 1/5). © 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 9: 305–320; 2009: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.200900017 相似文献
7.
Hiroyuki Tanaka Toshifumi Shiroya Minako Hanasaki Tatsushi Isojima Hisao Takeuchi Haruma Kawaguchi 《Macromolecular Symposia》2008,266(1):81-84
Summary: Protein chips are important tools for high-throughput analysis of biological events. We have developed a novel method to prepare a protein-based hydrogel, that is, a “Three-Dimensional Nano-structured Protein Hydrogel” (3-D NPH), which is composed of protein and polymer nano-particles. The 3-D NPH could be easily prepared by dispensing a protein and polymer mixture on a substrate. Surprisingly, gold particles conjugated with protein A diffused into the 3-D NPH which was made of mouse IgG through the pores. We have shown that the protein chips made with our 3-D NPH method has tremendously improved sensitivity in detecting protein-protein interactions compared with that of direct protein immobilization methods. 相似文献
8.
Ho Sik Kim Yoshihisa Kurasawa Chiemi Yoshii Minako Masuyama Atsushi Takada Yoshihisa Okamoto 《Journal of heterocyclic chemistry》1990,27(4):1119-1122
The isoxazolo[2,3-a]quinoxalines 11a,b and pyrrolo[1,2-a]quinoxalines 12a,b were selectively synthesized from the 2-substituted 6-chloroquinoxaline 4-oxides 10a,b . The pyrrolo[1,2-a]quinoxalines 12a,b were clarified to be produced by the ring transformation of the isoxazolo[2,3-a]quinoxalines 11a,b . The pyrrolo[1,2-a]quinoxalines 14a,b were obtained from both 2,6-dichloroquinoxaline 4-oxide 9 and compounds 12a,b . 相似文献
9.
In the presence of a catalytic amount of tetrakis(triphenylphosphine)platinum(0), allenes undergo carbonylative thiolation with carbon monoxide and thiols to provide the corresponding α,β- and β,γ-unsaturated thioesters in good yields. In contrast, the use of rhodium(I) catalysts such as RhH(CO)(PPh3)3 in place of Pt(PPh3)4 leads to copolymerization of allenes and carbon monoxide without incorporation of thio groups. 相似文献
10.
Takayoshi Tsuzuki Natsumi Sakaguchi Dr. Takashi Kudoh Satoshi Takano Masato Uehara Dr. Takashi Murayama Prof. Dr. Takashi Sakurai Dr. Minako Hashii Prof. Dr. Haruhiro Higashida Karin Weber Prof. Dr. Andreas H. Guse Dr. Tomoshi Kameda Dr. Takatsugu Hirokawa Dr. Yasuhiro Kumaki Prof. Dr. Barry V. L. Potter Dr. Hayato Fukuda Dr. Mitsuhiro Arisawa Prof. Dr. Satoshi Shuto 《Angewandte Chemie (International ed. in English)》2013,52(26):6633-6637