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61.
Tetsuji Kametani Kazuo Kigasawa Mineharu Hiiragi Kikuo Wakisaka Osamu Kusama Hideo Sugi Kumeo Kawasaki 《Journal of heterocyclic chemistry》1977,14(7):1175-1182
1H- and 2H-Pyrazolo[3,4-f]quinolines were synthesized in order to get an antibacterial compound by two different methods from 6-nitro- and 6-aminoindazole. 相似文献
62.
Yamamoto T Kusama M Matsuno K Sugiyama E Yamada Y Iga T 《Biomedical chromatography : BMC》2002,16(7):453-454
Buformin is a widely used as an antidiabetic agent but its renal excretion is still controversial. A new HPLC method with ultraviolet (UV) detection for the determination of buformin in plasma and urine has been developed. After protein precipitation or dilution, buformin and internal standard phenformin were resolved on an octadecyl silica column and detected by UV detection at 233 nm. Intra- and inter-day coefficients of variation were <9%. The limit of quantification was around 0.05 micro g/ml for plasma and 2.5 micro g/ml for urine. 相似文献
63.
[reaction: see text] A highly useful method for the construction of polycyclic compounds based on the amine-controlled exo- and endo-selective cyclizations of omega-alkynyl silyl enol ethers catalyzed by W(CO)5L is reported. When bis-alkynyl silyl enol ethers were treated with a catalytic amount of W(CO)6, DABCO, and water under photoirradiation, synthetically useful tricyclic ketones were obtained in good yield. 相似文献
64.
Polyphenols from Eriobotrya japonica and their cytotoxicity against human oral tumor cell lines 总被引:16,自引:0,他引:16
Ito H Kobayashi E Takamatsu Y Li SH Hatano T Sakagami H Kusama K Satoh K Sugita D Shimura S Itoh Y Yoshida T 《Chemical & pharmaceutical bulletin》2000,48(5):687-693
Three new flavonoid glycosides, together with 15 known flavonoids, have been isolated from the leaves of Eriobotrya japonica, and characterized as (2S)- and (2R)-naringenin 8-C-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosides, and cinchonain Id 7-O-beta-D-glucopyranoside, respectively, based on spectral analyses including two dimensional (2D) NMR techniques. Higher proanthocyanidin fraction in the water-soluble portion of the extract was characterized as a procyanidin oligomer mixture mainly composed of undecameric procyanidin. These polyphenols have also been assessed for cytotoxic activity against two human oral tumor (human squamous cell carcinoma and human salivary gland tumor) cell lines. Selective cytotoxicity of the procyanidin oligomer between tumor and normal gingival fibroblast cells, and its possible mechanism, were also described. 相似文献
65.
Kusama H Funami H Shido M Hara Y Takaya J Iwasawa N 《Journal of the American Chemical Society》2005,127(8):2709-2716
Novel tungsten-containing carbonyl ylides 7, generated by the reaction of the o-alkynylphenyl carbonyl derivatives 1 with a catalytic amount of W(CO)(5)(thf), reacted with alkenes to give polycyclic compounds 5 through [3 + 2]-cycloaddition reaction followed by intramolecular C-H insertion of the produced nonstabilized carbene complex intermediates 8. In the presence of triethylsilane, these tungsten-containing carbene intermediates 8 were smoothly trapped intermolecularly by triethylsilane to give silicon-containing cycloadducts 17 with regeneration of the W(CO)(5) species. By this procedure, the scope of alkenes employable for this reaction was clarified. The presence of the tungsten-containing carbonyl ylide 7c was confirmed by direct observation of the mixture of o-ethynylphenyl ketone 1c and W(CO)(5)(thf-d(8)). Careful analysis of the intermediate by 2D NMR, along with the observation of the direct coupling with tungsten-183 employing the (13)C-labeled substrate, confirmed the structure of the ylide 7c. Examination using (E)- or (Z)- vinyl ether revealed that the [3 + 2]-cycloaddition reaction proceeded in a concerted manner and that the facial selectivity of the reaction differed considerably depending on the presence or absence of triethylsilane. These results clarified the reversible nature of this [3 + 2]-cycloaddition reaction. 相似文献
66.
When omega-acetylenic dienol silyl ethers containing NMs part in the tether were treated with a catalytic amount of W(CO)6 under photoirradiation, 2-azabicyclo[3.3.0]octanes were obtained in good yield via pi-alkyne complexes. On the other hand, treatment of the same substrates with a catalytic amount of W(CO)6 in the presence of n-Bu3N under the same reaction conditions gave 3-azabicyclo[3.3.0]octanes in good yield exclusively via vinylidene complexes. Thus, the pi-alkyne and vinylidene complex pathways are easily controlled by using a catalytic amount of W(CO)5(L) and an amine. 相似文献
67.
Takahashi A Hirose Y Kusama H Iwasawa N 《Chemical communications (Cambridge, England)》2008,(5):609-611
An efficient method for the synthesis of substituted 5,6-dihydro-1,10-phenanthrolines and 1,10-phenanthrolines has been developed by means of the chelation-assisted photochemical electrocyclic reactions of 3-alkenyl-2,2'-bipyridines. 相似文献
68.
69.
Hiroshi Harada Takuro Endo Yasunori Momose Hiroshi Kusama 《Rapid communications in mass spectrometry : RCM》2009,23(5):564-570
The detection of the reactive metabolites of drugs has recently been gaining increasing importance. In vitro trapping studies using trapping agents such as glutathione are usually conducted for the detection of reactive metabolites, especially those of cytochrome P450‐mediated metabolism. In order to detect the UDP‐glucuronosyltransferase (UGT)‐mediated bioactivation of drugs, an in vitro trapping method using N‐acetylcysteine (NAC) as a trapping agent followed by liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed in this study. After the test compounds (diclofenac and ketoprofen) had been incubated in human liver microsomes with uridine diphosphoglucuronic acid (UDPGA) and NAC, the NAC adducts formed through their acyl glucuronides were analyzed using LC/MS/MS with electrospray ionization (ESI). The NAC adduct showed a mass shift of 145 units as compared to its parent, and the characteristic ion fragmentations reflected the parent. This is a concise and high‐throughput method for evaluating reactive metabolites by UGT‐mediated bioactivation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
70.