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91.
Phytochemical analyses were carried out on the rhizomes of Clintonia udensis (Liliaceae) with particular attention paid to the steroidal glycoside constituents, resulting in the isolation of three new polyhydroxylated spirostanol glycosides, named clintonioside A ( 1 ), B ( 2 ), and C ( 3 ). On the basis of their spectroscopic data, including 2D‐NMR spectroscopy, in combination with acetylation and hydrolytic cleavage, the structures of 1 – 3 were determined to be (1β,3β,23S,24S,25R)‐1,23,24‐trihydroxyspirost‐5‐en‐3‐yl O‐β‐D ‐glucopyranosyl‐(1→4)‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)]‐β‐D ‐glucopyranoside ( 1 ), (1β,3β,23S,24S)‐3,21,23,24‐tetrahydroxyspirosta‐5,25(27)‐dien‐1‐yl O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 2 ), and (1β,3β,23S,24S)‐21‐(acetyloxy)‐24‐[(6‐deoxy‐β‐D ‐gulopyranosyl)oxy]‐3,23‐dihydroxyspirosta‐5,25(27)‐dien‐1‐yl O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[β‐D ‐xylopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 3 ). 相似文献
92.
A variety of N-confused tetraphenylporphyrin rhodium complexes were synthesized, and their structures and physical properties were investigated. Depending on the reaction conditions, the rhodium(I), -(III), and -(IV) complexes were produced, which exemplified the versatile coordination mode of N-confused porphyrin ligands. 相似文献
93.
A Bulky Thiyl‐Radical Catalyst for the [3+2] Cyclization of N‐Tosyl Vinylaziridines and Alkenes 下载免费PDF全文
Dr. Takuya Hashimoto Kohei Takino Kazuki Hato Prof. Dr. Keiji Maruoka 《Angewandte Chemie (International ed. in English)》2016,55(28):8081-8085
Thiyl‐radical‐catalyzed cyclization reactions of N‐tosyl vinylaziridines and alkenes were developed as a new synthetic method for the generation of substituted pyrrolidines. The key to making this process accessible to a broad range of substrates is the use of a sterically demanding thiyl radical, which prevents the undesired degradation of the catalyst. 相似文献
94.
Kazuki Aoki Nakao Hayashi Pavel I. Naumkin 《NoDEA : Nonlinear Differential Equations and Applications》2016,23(6):65
We consider the Cauchy problem for the fourth-order nonlinear Schrödinger equation where \(n=1,2\). We prove global existence of small solutions under the growth condition of \(f\left( u\right) \) satisfying \(\left| \partial _{u}^{j}f\left( u\right) \right| \le C\left| u\right| ^{p-j},\) where \(p>1+\frac{4}{n},0\le j\le 3\).
相似文献
95.
96.
Prof. Dr. Katsuhiro Isozaki Tomoya Yokoi Ryota Yoshida Dr. Kazuki Ogata Dr. Daisuke Hashizume Dr. Nobuhiro Yasuda Prof. Dr. Koichiro Sadakane Prof. Dr. Hikaru Takaya Prof. Dr. Masaharu Nakamura 《化学:亚洲杂志》2016,11(7):1076-1091
Two (ONO pincer)ruthenium‐complex‐bound norvalines, Boc?[Ru(pydc)(terpy)]Nva?OMe ( 1 ; Boc=tert‐butyloxycarbonyl, terpy=terpyridyl, Nva=norvaline) and Boc?[Ru(pydc)(tBu‐terpy)]Nva?OMe ( 5 ), were successfully synthesized and their molecular structures and absolute configurations were unequivocally determined by single‐crystal X‐ray diffraction. The robustness of the pincer Ru complexes and norvaline scaffolds against acidic/basic, oxidizing, and high‐temperature conditions enabled us to perform selective transformations of the N‐Boc and C?OMe termini into various functional groups, such as alkyl amide, alkyl urea, and polyether groups, without the loss of the Ru center or enantiomeric purity. The resulting dialkylated Ru‐bound norvaline, n‐C11H23CO?l ‐[Ru(pydc)(terpy)]Nva?NH‐n‐C11H23 (l ‐ 4 ) was found to have excellent self‐assembly properties in organic solvents, thereby affording the corresponding supramolecular gels. Ru‐bound norvaline l ‐ 1 exhibited a higher catalytic activity for the oxidation of alcohols by H2O2 than parent complex [Ru(pydc)(terpy)] ( 11 a ). 相似文献
97.
This article describes the relationships between not only comonomer-unit compositions but also their distributions and structures as well as properties for bacterial copoly(hydroxyalkanoate)s, including poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxy-propionate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxy-butyrate-co-4-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-mercapto-propionate). It was found that as-produced copoly(hydroxy-alkanoate)s have broad comonomer-unit compositional distributions, which we can control to some degree. The structure and properties of copoly(hydroxy-alkanoate)s depend not only on the chemical structure and the comonomer-unit composition but also on the comonomer-unit compositional distribution. 相似文献
98.
Kazuki Miyake Per B. Zetterlund Bunichiro Yamada 《Macromolecular rapid communications》2004,25(22):1905-1911
Summary: Experimental and modeling studies of addition–fragmentation chain transfer (AFCT) during radical polymerization of methyl methacrylate in the presence of poly(methyl methacrylate) macromonomer with 2‐carbomethoxy‐2‐propenyl ω‐ends (PMMA‐CO2Me) at 60 °C are reported. The results revealed that AFCT involving PMMA‐CO2Me formed in situ during methyl methacrylate polymerization has a negligible effect on the molecular weight distribution.
99.
The conventional measurement of ABO blood-types is visual inspection method based on the aggregation reaction with monoclonal antibody. But, this method takes a long time (one night) and requires the skilled analyzer to decide the blood-types for the saliva and bloodstain sample. Therefore, the rapid and sensitive measurement of ABO blood type has been required for the saliva and bloodstain on the clothes. Surface prasmon resonance (SPR) is an optical technique, which has been applied to biosensing. In this study, the rapid and sensitive measurement of ABO blood-types were investigated by using SPR sensing system. 相似文献
100.