All issues
Volume 46, Issue 12
Displaying 1-25 of 25 articles from this issue
- |<
- <
- 1
- >
- >|
-
Yoshiko NAGATA, Reiko YODA, Yoshikazu MATSUSHIMA1998 Volume 46 Issue 12 Pages 1849-1852
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSCourse of the formation of a quinonoid species absorbing in the 500-nm region, which should serve as a model for the key intermediate in reactions catalyzed by pyridoxal phosphate enzymes, was studied in the reaction of pyridoxal, ethyl L-alaninate and Al(III) in methanol by means of UV-visible spectroscopy, chromatography with a multi-UV detector, optical rotation and 1H-NMR. The species was chromatographically separated in the form of the Al(III) chelate and its quantitative transformation to the aldimine chelate was observed. The formation of the species in the transamination reaction of pyridoxamine, ethyl pyruvate and Al(III) was also studied.View full abstractDownload PDF (614K) -
ATTA-UR RAHMAN, M. Iqbal CHOUDHARY, Muhammad YOUSAF, Waseem GUL, Samin ...1998 Volume 46 Issue 12 Pages 1853-1856
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree new withanolides, coagulins M, N, and O were isolated from the whole plant of Withania coagulans. Their structures were established as (14R, 17R, 20ζ, 22R)-5α, 6β, 27-trihydroxy-14, 20-epoxy-1-oxo-witha-24-enolide (1), (14R, 17S, 20ζ, 22R)-15α, 17-dihydroxy-14, 20-epoxy-3β-(O-β-D-glucopyranosyl)-1-oxo-witha-5, 24-dienolide (2) and (14R, 20ζ, 22R)-14, 20-dihydroxy-3β-(O-β-D-glucopyranosyl)-1-oxo-witha-5, 24-dienolide (3) respectively, by extensive spectroscopic studies.View full abstractDownload PDF (725K) -
Masao NAGAOKA, Etsuko NAGASAWA, Mitsuteru NUMAZAWA1998 Volume 46 Issue 12 Pages 1857-1861
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSReaction of various steroidal 16, 17-ketols, 16α-hydroxy-17-ketones 1-3, and 15, 16β-hydroxy-17-ketone 4, and 17β-hydroxy-16-ketones 5-7, and 17, along with methyl ethers of 16α- and 17β-ketols, 1 and 5, with an excess of trimethylsilyl iodide (TMSI) or with HI in CHCl3, produced the deoxygenated products, a mixture of the corresponding 17-and 16-ketones, in low to quantitative yields, in which the 17-ketone was the major product in each case. When the 16β-deuterated 16α-ketol 3 and the 17α-deuterated 17β-ketol 7 were reached with TMSI for a brief period (15 min), the deuterium content at C-16β and C-17α of the recovered steroids 3 and 7 was reduced by 17 and 35%, respectively. The present results indicate that the deoxygenation proceeds not only through a direct iodination pathway producing α-iodoketone but also through other reaction pathways.View full abstractDownload PDF (806K) -
Michiharu SUGIURA, Koosuke ASAI, Yoshiki HAMADA, Keiichiro HATANO, Yuk ...1998 Volume 46 Issue 12 Pages 1862-1865
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS2-Acyl(or sulfonyl)-c-4-bromo-γ-1-cyano-t-3-methoxy-1, 2, 3, 4-tetrahydroisoquinolines 2b-g when treated with triethylamine or K2CO3 gave cyclodimers 5b-g of 2-acyl(or sulfonyl)-1-cyano-3-methoxy-2, 3-dihydroisoquinolines in high yields. The dimers are composed of two tetrahydroisoquinoline units fused at the 1, 1'- and 4, 4'-positions to form a triheterocyclic 3, 7-diazatricyclo[4.2.2.22, 5]dodeca-9, 11-diene ring. 2, 3-Dihydroisoquinoline type compounds 3 are the key intermediate for this unusual [4+4] cyclodimerization. The structures of the dimers with an exo-type configuration have been determined by X-ray crystallography. The reaction mechanism of the cyclodimerization is discussed in conjunction with the stereochemistry of the products.View full abstractDownload PDF (643K) -
Akikazu KAKEHI, Suketaka ITO, Hiroyuki SUGA, Toshiyuki KOBAYASHI, Susu ...1998 Volume 46 Issue 12 Pages 1866-1871
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe reactions of (Z)-3-[mercapto(methylthio)methylene]-2(3H)-indolizinones with bromoacetonitrile and bromoacetates in the presence of a base gave the corresponding 4(1H)-8, 8a-dihydro-1, 4-thiazino[3, 4, 5-cd]indolizinone derivatives, but similar treatment of the same compounds with some phenacyl bromides provided a quite different type of product, (E)-3-(5-aryl-1, 3-oxathiol-2-ylidene)-2(3H)-indolizinones, in 12-74% yield with the evolution of methanethiol. Interestingly, the reactions of (Z)-3-[mercapto(phenacylthio)methylene]-2(3H)-indolizinones and iodomethane in the presence of a base did not afford the expected (Z)-3-(5-aryl-1, 3-oxathiol-2-ylidene)-2(3H)-indolizinones, but gave only the same (E)-isomers in 22-53% yields. The stereochemistry about the C3-C2' double bond in these 3-(5-aryl-1, 3-oxathiol-2-ylidene)-2(3H)-indolizinones was determined to be (E) by X-ray analysis.View full abstractDownload PDF (949K) -
Kunihiko MOHRI, Kimiaki ISOBE, Manabu MAEDA, Taroh TAKEDA, Ryoko OHKUB ...1998 Volume 46 Issue 12 Pages 1872-1877
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe skeletal structure of cocculolidine (1), a D-nor-erythinan alkaloid, was synthesized as the 8-oxo derivative 2 by several routes via the diester 4 as a key intermediate. One route was an ozonolysis of 14, 15, 17-trimethoxy-8-oxo-erythrinan (3) to directly yield 4 in 63%. The other was the Ce(IV) methanesulfonate oxidation of 16, 17-dimethoxy-8-oxo-erythinan (6) to yield the p-quinone 7 (94%), which was converted to the same diester 4 by ozonolysis and peroxide oxidation (70%). The diester 4 was transformed to the corresponding anhydride 5, which was regioselectively reduced with a bulky borohydride (K-selectride[○!R]) to give the desired lactone 2.View full abstractDownload PDF (784K) -
Akihiro IMURA, Motohiro ITOH, Akihiko MIYADERA1998 Volume 46 Issue 12 Pages 1878-1880
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe key intermediate of a 20(S)-camptothecin 1 synthesis was obtained in a highly enantioselective fashion using an enzyme-catalyzed resolution. A commercially available protease was found to exhibit the highest enantioselectivity with moderate activity, and (S)-ethyl 2-acetoxy-2[6-(acetoxymethyl)-1, 1-(ethylenedioxy)-5-oxo-1, 2, 3, 5-tetrahydroindolizin-7-yl]butanoate 7c of 98% e.e. was obtained as the remaining substrate.View full abstractDownload PDF (568K) -
Takuji KAKIGAMI, Nobuaki TSURUTA, Katsura TSUKAMOTO, Toshinao USUI, Ta ...1998 Volume 46 Issue 12 Pages 1881-1886
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA 3D-quantitative structure-activity relationship (3D-QSAR) study was carried out using comparative molecular field analysis (CoMFA) of the 5-HT4 agonistic activity of benzamide type compounds, which had been already synthesized and reported to show 5-HT4 agonistic activity. The chosen alignment yielded a good cross-validated result (γ-2cv=0.628). This CoMFA model was able to predict the 5-HT4 agonistic activity of three structurally different compounds. Consequently, 5-amino-N-[2-(1-azabicyclo[3.3.0]octan-5-yl)ethyl]-6-chloro-3, 4-dihydo-2H-1-benzopyran-8-carboxamide (22) was obtained as the most potent 5-HT4 agonist.View full abstractDownload PDF (878K) -
Masafumi OHKAWA, Junei KINJO, Yoshihide HAGIWARA, Hideaki HAGIWARA, Hi ...1998 Volume 46 Issue 12 Pages 1887-1890
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree new saponarin analogs, 6'''-sinapoylsaponarin, 6'''-feruloysaponarin and 4'-glucosyl-6'''-sinapoyl-saponarin were isolated together with four known compounds from young green barley (Hordeum vulgare var. nudum) leaves. Their anti-oxidative effects towards superoxide, photo-oxidation of vitamins and the 1, 1-diphenyl-2-picrylhydrazyl radical were tested. The superoxide-scavenging activity depended on the number of free hydroxy groups. In contrast, the inhibition of vitamin oxidation seemed to be due to the flavone skeleton. In addition, the sinapoyl moiety seemed to be important for radical-scavenging activity.View full abstractDownload PDF (646K) -
Yukio KAWATA, Haruhisa KIZU, Tsuyoshi TOMIMORI1998 Volume 46 Issue 12 Pages 1891-1900
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom the roots of Clematis terniflora, nine new oleanolic acid 3, 28-O-bisdesmosides called clematernosides A, B, E, F, G, H, I, J and K, and two new hederagenin 3, 28-O-bisdesmosides called clematernosides C and D, have been isolated together with two known saponins, huzhangoside B and clematichinenoside C. The structures of the new saponins have been elucidated based on chemical and spectral evidence. Among the new saponins, clematernosides I and J have a nonsaccharide moiety and a total of twelve monosaccharide moieties in the molecule. This is the first report of the isolation and structure elucidatin of such "big" glycosides.View full abstractDownload PDF (1302K) -
Isao KITAGAWA, Kazuyuki HORI, Tomohisa MOTOZAWA, Toshiyuki MURAKAMI, M ...1998 Volume 46 Issue 12 Pages 1901-1906
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo new acylated oleanene-type triterpene oligoglycosides, theasaponins E1 and E2, were isolated from the seeds ofb tea plant [Camellia sinensis (L.) O. KUNTZE]. The structures of theasaponins E1 and E2 were elucidated on the basis of chemical and physiochemical evidence to be expressed as 21-O-angeloyl-22-O-acetyltheasapogenol E 3-O-[β-D-galactopyranosyl (1→2)][β-D-xylopyranosyl](1→2)-α-L-arabinopyranosyl (1→3)]-β-D-glucopyranosiduronic acid and 21-O-angeloyl-28-O-acetyltheasapogenol E 3-O-[β-D-galactopyranosyl (1→2)] [β-D-xylopyranosyl (1→2)-α-L-arabinopyranosyl (1→3)]-β-D-glucopyranosiduronic acid, respectively. Theasaponin E1 was found to show antisweet activity.View full abstractDownload PDF (894K) -
Hideki ISHIWATA, Satoshi B. SATO, Satoe KOBAYASHI, Masahide OKU, Aline ...1998 Volume 46 Issue 12 Pages 1907-1913
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSLiposome uptake by HepG2 human hepatoma cells was investigated in comparison with the uptake by J774 murine macrophage-like cells. HepG2 cells accumulated liposomes (egg yolk phosphatidylcholine (EPC)/Chol; 75/25, diameter 0.2 μm) at 37°C comparably to J774 macrophage-like cells. Confocal microscopic observations revealed that J774 cells internalized EPC/Chol liposomes efficiently but HepG2 cells kept most or the liposomes bound on their plasma membrane surfaces. Poly(ethylene glycol) (PEG)-coated liposomes (0.2 μm) containing poly(ethylene glycol) cholesteryl ether (PEG-Chol) avoided cellular uptake at 37°C by either cell line. In both cell lines, binding of PEG-coated liposomes was lower than that of EPC/Chol liposomes when incubation was carried out at 4°C. To analyze the binding process at 37°C, surface-bound liposomes were removed from the cells by pronase treatment. A reduction of the amount of bound-liposomes on cell surfaces was observed in the case of PEG-coated liposomes. Therefore, PEG/coating reduces direct binding of liposomes to the cell surfaces. The presence of apolipoprotein E (apoE) increased the uptake of EPC/Chol liposomes via its receptor in both cell lines. In contrast, cellular uptake of PEG-coated liposomes was not enhanced by treatment with apoE. Therefore, while apoE-mediated liposome uptake occurs in the case of EPC/Chol liposomes, it does not occur for PEAG-coated liposomes; PEG-coating also inhibits protein-mediated binding to the cells. These results further imply that elusion from liver clearance of PEG-coated liposomes is not only due to the reduction of uptake by Kupffer cells but also by hepatocytes when liposomes are small enough to go through the fenestrates of the endothelial lining.View full abstractDownload PDF (1262K) -
Shinji AOKI, Kazumi DANJO1998 Volume 46 Issue 12 Pages 1914-1917
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSWe studied the dissolution and absorption of ibuprofen (IB) from a three-layer tablet : the 1st layer (CIB layer) consisted of IB which was coated with anhydrous silicic acid (CIB), the 2nd layer was bromovalerylurea and anhydrous caffeine, and the 3rd layer was bromovalerylurea and ethenzamide. Differential scanning calorimetry and powder X-ray diffraction studies showed that the crystallinity of IB was not influenced by the preparation of CIB. The dissolution and absorption of IB from the CIB layer of the three-layer tablet were compared with those of a commercial tablet. In a test solution at pH 1.2, the dissolution rate of IB from the CIB layer was higher than that from the commercial tablet; moreover, the time for peak concentration (Tmax) after administration of the CIB layer was significantly shorter. The Tmax of the CIB layer tablet was about 52 min, while that of the commercial tablet was about 103 min. The rapid dissolution and absorption of IB in the CIB layer may be dur to enhanced permeation, disintegration and dissaggregation of CIB.View full abstractDownload PDF (791K) -
Shin-ichi KONDO, Shouichi HOSAKA, Isao HATAKEYAMA, Masayuki KUZUYA1998 Volume 46 Issue 12 Pages 1918-1923
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSWe theoretically derived rate equation of drug release from a simple model in a heterogeneous system. Four assumptions were used to simplify the model. Two kinds of rate equations for drug release derived from two possible limiting cases, that the rate-determining step is a diffusion of hydrolysis controlled process, can predict the experimental results up to 50% hydrolysis. However, the predictions at the later stage by these equations are insufficient. These results suggest that the process of drug release from powdered polymeric prodrugs in a heterogeneous system must be described by both diffusion and hydrolysis. The rate equation derived from a model considering both the diffusion and hydrolysis processes can successfully predict the experimental results for several kinds of polymeric prodrugs. It is also shown that the diffusion coefficient and rate constant for hydrolysis calculated from this equation thoroughly express the character of the comonomer. The rate equation derived from the model that considers both diffusion and hydrolysis is very useful to analyze drug release from various kinds of polymeric prodrugs in a heterogeneous system.View full abstractDownload PDF (817K) -
Hitomi SASAKI, Masaaki OHARA1998 Volume 46 Issue 12 Pages 1924-1925
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA newly prepared copper(II)-complexed β-cyclodextrin plymer cross-linked with epichorohydrin was used as a packing material with a strongly alkaline eluate for the liquid chromatography of nucleosides. Nucleosides such as adenosine and cytidine were retained on the column because of their strong interaction with copper(II) ions. On the other hand, 2'-deoxydanosine was retained on the copper(II)-free and copper(II)-complexed columns because of the inclusion property of β-cyclodextrin. These findings indicate that chromatography separations can be achieved by the inclusion effect and copper(II)-complexation.View full abstractDownload PDF (395K) -
Christoph SEGER, Srunya VAJRODAYA, Harald GREGER, Otmar HOFER1998 Volume 46 Issue 12 Pages 1926-1928
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new quinazolone derivative, (Z)-3, 4-dihydro-3-(2-phenylethenyl)-quinazolin-4-one, was isolated from Glycosmis cf. chlorsperma SPRENG. (Rutaceae). The structure was elucidated on the basis of spectroscopic data and confirmed by comparison with synthetically obtained material. The compound showed bioactivity against different test organisms.View full abstractDownload PDF (494K) -
Akihiro UENO, Hiroshi OHASHI, Toyoo NAKANO, Kaname KIMURA, Toshiyuki S ...1998 Volume 46 Issue 12 Pages 1929-1931
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe crystal structures of sulochrin derivatives, sulochrin triacetate (2) and sulochrin 4-(4'-bromobenzoate) (3), were determined. Triacetyl derivative 2 was in a conformation where the planes of two aromatic rings and the central carbonyl plane were all oblique to each other. Compound 3 was in a conformation where ring B and the central carbonyl planes were co-planar and crossed at a right angle to ring A plane, suggesting the effect of substituents at ortho positions on conformation of tetra ortho substituted benzophenones.View full abstractDownload PDF (434K) -
Hiroshi IWASAKI, Yoichi MIYAMOTO, Ryuzo HOSOTANI, Yoshio NAKANO, Katsu ...1998 Volume 46 Issue 12 Pages 1932-1935
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe syntheses and biological evaluations of (23R)- and (23S)-24, 24-difluoro-1α, 23, 25-trithydroxyvitamin D3 (3a and 3b), new C-24 fluorinated analogs of 1α, 25-dihydroxyvitamin D3, are described. The syntheses of these compounds were achieved in 3 steps from (5Z, 7E, 20R)-1α, 3β-bis-[(tert-butyldimethylsilyl)oxy]-20-formylmethyl-9, 10-seco-5, 7, 10(19)oregnatriene (5) which is derived from vitamin D2. The absolute configuration at the C-23 position of 3a and 3b was determined by the modified Mosher method. The relative affinities of 3a and 3b to the vitamin D receptor were both 10 and 14 times lower than that of 1α, 25-dihydroxyvitamin D3 (1), and to vitamin D binding protein were also both 130 and 40 times lower. The HL-60 cell differentiating activity of 3a was 6 times more potent than that of 1, while there was no remarkable difference in activity between 3b and 1.View full abstractDownload PDF (652K) -
Keiji TAKAHATA, Kuniharu OHGUCHI, Shukuro IGARASHI1998 Volume 46 Issue 12 Pages 1936-1938
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPeroxidase (POD) was found to act as an excellent catalyst during the oxidative decomposition reaction of the copper-phthalocyanine complex (Cu-pts) using peroxomonosulfate. POD also decomposed with Cu-pts during the reaction. Therefore, the simultaneous decomposition of indicator and catalyst provides a characteristic L-shape absorbance-time curve. Based on these findings, an indicator system of POD, which has a slight variation in the measured absorbance for time and high precision, was established. This spectrophotometry was able to make determination over the range of 0.1 to 30 μg/ml of POD. The detection limits (3σ) were 0.02 μg/ml and the relative standard deviation was 3.7% for 0.5 μg/ml of POD (10 determinations) The proposed method has been applied to the determination of human interleukin-8 which was added to human serum using POD as the label in an immunoassay.View full abstractDownload PDF (536K) -
Junichi KITAJIMA, Chieko OKAMURA, Toru ISHIKAWA, Yasuko TANAKA1998 Volume 46 Issue 12 Pages 1939-1940
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new hemiterpenoid glycoside, phenylpropanoid glycoside, and furocoumarin were isolated from the methanolic extract of the root and rhizoma of Glehnia littoralis FR. SCHMIDT ex MIQ. (Umbelliferae, "Hamabofu" in Japanese). Their structures were determined by the spectral investigations.View full abstractDownload PDF (425K) -
Shigeki HASHIMOTO, Yushin NAKAMURA1998 Volume 46 Issue 12 Pages 1941-1943
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSBisnetropsin-linked hydroxamic acids (BHNA) were shown to cleave DNA strands at a single residue with a preferred binding orientation in the presence of ferrous ion. In constrast, the corresponding cerium (III) complexes cleaved DNA with low sequence specificity.View full abstractDownload PDF (679K) -
Redox Potential of Bacteriorhodopsin in Purple Membrane Determined by Differential Pulse VoltammetrySatoru UENO, Akira SHIBATA, Yoshihiro ITO1998 Volume 46 Issue 12 Pages 1944-1945
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSDifferential pulse voltammograms of bacteriorhodopsin (BR) in a purple membrane showed one redox peak at -781 mV for light-adapted BR and two redox peaks at -484 and -781 mV for dark-adapted BR. The redox potential did not significantly depend on pH in the range of 3.0 to 11.0 (about 5 mV/pH), indicating that a change in the protonation state was not involved in this redox process. The C=N bond in the Schiff base of BR is responsible for the observed redox reactions.View full abstractDownload PDF (405K) -
Masahiko TANIGUCHI, Yong-Qing XIAO, Xiao-Hong LIU, Akiko YABU, Youske ...1998 Volume 46 Issue 12 Pages 1946-1947
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo new spirotrifuranocoumarins, rivulotririns A and B (1 and 2), were isolated from the underground part of Pleurospermum rivulorum. They are characterized as two stereoisomers having a different configuration at the C-2 position resulting from the condensation of two heraclenol and one isogosferol units, respectively, on the basis of spectral analysis.View full abstractDownload PDF (351K) -
Hitomi HAGIWARA, Tominari CHOSHI, Hiroyuki FUJIMOTO, Eiichi SUGINO, Sa ...1998 Volume 46 Issue 12 Pages 1948-1949
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSStarting from 2-chloro-2-formylindole, new syntheses of murrayaquinone A and furostifoline were achieved by an allene-mediated electrocyclic reaction involving the indole 2, 3-bond.View full abstractDownload PDF (386K) -
Selective Inhibition of Src Protein Tyrosine Kinase by Analogues of 5-S-Glutathionyl-β-alanyl-L-dopaZhe-bin ZHENG, Sachie NAGAI, Naoko IWANAMI, Ayako KOBAYASHI, Mariko HI ...1998 Volume 46 Issue 12 Pages 1950-1951
Published: December 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwelve analogues of the antibacterial phenolic peptide 5-S-glutathionyl-β-alanyl-L-dopa (5-S-GA-L-D : 1) were synthesized via orthoquinones using tyrosinase. Several synthesized compounds inhibited the v-Src autophosphorylation tyrosine kinase reaction with an IC50 value comparable to that of herbimycin. The inhibition of c-Src substrate phosphorylation was much less active than v-Src autophosphorylation inhibition. The analogues showed no effects on substrate phosphorylation by epidermal growth factor receptor (EGFR), and this selectivity is the most characteristic feature of the analogues (1-12).View full abstractDownload PDF (405K)
- |<
- <
- 1
- >
- >|