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Volume 48, Issue 8
Displaying 1-31 of 31 articles from this issue
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Piera Di MARTINO, Giovanni Filippo PALMIERI, Sante MARTELLI2000 Volume 48 Issue 8 Pages 1105-1108
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe purpose of this paper is to study the molecular mobility of paracetamol molecules in their amorphous state below the glass transition temperature (Tg) in order to evaluate the thermodynamic driving force which allows the amorphous form to recrystallize under different polymorphic modifications. Samples were aged at temperatures of -15, 0, 6, and 12°C for periods of time from 1 h to a maximum of 360 h. The extent of physical aging was measured by a DSC study of enthalpy recovery in the glass transition region. The onset temperature of glass transition was also determined (Tg). Enthalpy recovery (ΔH) and change in heat capacity (ΔCp) were used to calculate the mean molecular relaxation time constant (τ) using the empirical Kohlausch-Williams-Watts (KWW) equation. Enthalpy recovery and onset glass transition temperature increased gradually with aging and aging temperatures. Structural equilibrium was reached experimentally only at an aging temperature of 12°C (Tg-10°C), according to the ΔH∞ results. The experimental model used is appropriate only at lower aging temperatures, while at higher ones the complexity of the system increases and molecular polymorphic arrangement could be involved. When structural equilibrium is experimentally reached, molecules can be arranged in their lowest energy state, and the polymorphic form I formation is the one preferred.View full abstractDownload PDF (618K) -
Li-Quan WANG, Norio NAKAMURA, Meselhy R. MESELHY, Masao HATTORI, Wei-M ...2000 Volume 48 Issue 8 Pages 1109-1113
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFour novel mono-tetrahydrofuran (THF) acetogenins, montanacins B-E (1-4), were isolated from the ethanolic extract of the leaves of Annona montana. The structures of 1-4 were established by spectroscopic methods and their absolute stereochemistries were determined by the advanced Mosher ester method. Montancins D (3) and E (4) bear a non-adjacent tetrahydropyran (THP) ring along with a THF ring and are the most unusual type of acetogenins discovered so far.View full abstractDownload PDF (705K) -
I Ketut ADNYANA, Yasuhiro TEZUKA, Suresh AWALE, Arjun Hari BANSKOTA, K ...2000 Volume 48 Issue 8 Pages 1114-1120
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSix new triterpene glucosides, quadranosides VI-XI (1-6), belonging to three different [ursane- (1-4), oleanane- (5) and lupane-type (6)] triterpene classes, have been isolated from a MeOH extract of the seeds of Combretum quadrangulare KURZ (Combretaceae), together with nine known compounds, rosamutin (7), 28-O-β-D-glucopyranosyl-6β, 23-dihydroxytormentic acid (8), arjunetin (9), arjunglucoside II (10), combreglucoside (11), chebuloside II (12), vitexin (13), (+)-catechin (14) and (-)-epigallocatechin (15). The structures of these compounds were elucidated by spectroscopic analysis.View full abstractDownload PDF (824K) -
Mitsuru OKA, Yukiharu MATSUMOTO, Kiyotaka HIROOKA, Tomoo SUZUKI2000 Volume 48 Issue 8 Pages 1121-1124
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA useful pharmaceutical intermediate, 5-nitromethyl-1-azabicyclo[3.3.0]octane (1), was prepared in one step from 1, 7-dichloro-4-heptanone (4) under mild conditions. Catalytic hydrogenation of 1 over Raney Ni in the presence of sodium hydroxide afforded 5-aminomethyl-1-azabicyclo[3.3.0]octane (2) in high yield. Piracetam analogues 20-23, which were pyrrolidine derivatives involving a 1-azabicyclo[3.3.0]octane ring, were synthesized.Pharmacological tests showed that N-[(1-azabicyclo[3.3.0]octan-5-yl)methyl]-2-oxo-1-pyrrolidineacetamide (20) improves cerebral function.View full abstractDownload PDF (675K) -
Hideki YANO, Fumitoshi HIRAYAMA, Hidetoshi ARIMA, Kaneto UEKAMA2000 Volume 48 Issue 8 Pages 1125-1128
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPrednisolone 21-hemisuccinate/β-cyclodextrin (β-CyD) amide conjugate was prepared by binding prednisolone 21-hemisuccinate covalently to the amino group of mono(6-deoxy-6-amino)-β-CyD through amide linkage. Prednisolone 21-hemisuccinate was intramolecularly transformed to prednisolone 17-hemisuccinate, and the parent drug, prednisolone, was slowly released from the 21-hemisuccinate with a half life of 69 h in pH 7.0 at 37°C; the drug release at 25°C was less than 10% for 48 h. In sharp contrast, the hydrolysis of prednisolone 21-hemisuccinate/β-CyD amide conjugate was significantly faster (half life of 6.50 min at 25°C) and gave prednisolone and mono(6-deoxy-6-succimino)-β-CyD as products. The hydrolysis of the β-CyD amide conjugate was subject to a specific-base catalysis in the alkaline region. The rapid hydrolysis of the conjugate can be ascribed to the involvement of an intramolecular nucleophilic catalysis of the amide group in the reaction. The succinic acid, bound to a drug through ester linkage at one carboxylic group and bound to a pro-moiety through amide linkage at another carboxylic group, may be useful as a spacer for construction of the immediate release type prodrugs of CyDs.View full abstractDownload PDF (601K) -
Akira MIZUNO, Mikiko MIYA, Tomoe KAMEI, Makoto SHIBATA, Toshio TATSUOK ...2000 Volume 48 Issue 8 Pages 1129-1137
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAs an extension of our previous investigation, a series of 7-aminoalkylpyrrolo[2, 3-c]azepine derivatives was synthesized and evaluated as α1-adrenergic- and serotonin 2(5-HT2)-receptor antagonists, with the aim of finding a novel potent antihypertensive agent with both activities. Among the compounds obtained in this study, (E)-1-ethyl-7-[3-[4-(4-fluorophenyl)piperazin-1-yl]propyl]-4-hydroxyimino-1, 4, 5, 6, 7, 8-hexahydropyrrolo[2, 3-c]azepin-8-one (16d) displayed potent α1-adrenoceptor blocking activity (pA2=7.83±0.20) and 5-HT2-receptor blocking activity (pA2=9.47±0.17) in isolated guinea pig arteries. At 3 mg/kg oral administration, compound 16d exhibited antihypertensive activity more potent than that of doxazosin in deoxycorticosterone acetate (DOCA)-salt hypertensive dogs. Furthermore, this compound reduced the rate of mouse acute pulmonary thromboembolitic death induced by collagen and serotonin at oral doses of 0.3 mg/kg or more, and its effect lasted for at least 6 h at 3 mg/kg.View full abstractDownload PDF (1382K) -
The Effect of Phenyl Substituents on the Release Rates of Esterase-Sensitive Coumarin-Based ProdrugsYuan LIAO, Siska HENDRATA, Sung Yong BAE, Binghe WANG2000 Volume 48 Issue 8 Pages 1138-1147
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA coumarin-based prodrug system has been recently developed in our laboratory for the preparation of esterase-sensitive prodrugs of amines, peptides, and peptidomimetics. The drug release rates from this prodrug system were found to be dependent on the structural features of the drug moiety. In certain cases, the release can be undesirably slow for drugs that are secondary amines with relatively high pKa's. Aimed at finding ways to manipulate the release rates to suit the need of different drugs, we have examined the effect of the phenyl ring substitutions on the release kinetics of such prodrugs and found that appropriately positioned alkyl substituents on the phenyl ring could help to facilitate the release by as much as 16-fold. Therefore, introduction of alkyl substituents on the phenyl ring should allow us to manipulate the release rates and, therefore, time profiles for different drugs.View full abstractDownload PDF (1640K) -
Hiroyuki ITOH, Rieko YONEDA, Junzo TOBITSUKA, Tadashi MATSUHISA, Hisak ...2000 Volume 48 Issue 8 Pages 1148-1153
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new series of azole derivatives containing silicon were synthesized and evaluated for fungicidal activity against rice sheath blight by submerged application. Among them, 2-(4-fluorophenyl)-1-(1H-1, 2, 4-triazol-1-yl)-3-trimethylsilylpropan-2-ol (9a) exhibited satisfactory efficacy at 12.5 grams per 10 ares.View full abstractDownload PDF (875K) -
Satoru WATANO, Tetsuya NUMA, Kei MIYANAMI, Yoshifumi OSAKO2000 Volume 48 Issue 8 Pages 1154-1159
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA novel system has been developed to continuously monitor granule growth in a high shear granulation. The system consists of an image processing system and a particle image probe comprising a CCD camera, lighting unit and air purge system. Segregation during powder mixing was investigated experimentally and the optimal positioning of the probe was determined.High shear granulation was conducted using pharmaceutical powders, and granule size and product's yield of various size ranges were continuously measured by the developed system. Sieve analysis of the granulated products sampled out during the granulation was simultaneously conducted, and the obtained data was compared with that by the on-line image processing system. An extremely close relationship could be found between both data, proving that the developed system could monitor the granule growth accurately and continuously throughout the granulation. An on-off control system was developed to control the granulation process, and the performance of the system was confirmed.View full abstractDownload PDF (1149K) -
Noriyasu HADA, Mayuko KURODA, Tadahiro TAKEDA2000 Volume 48 Issue 8 Pages 1160-1165
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSNovel neutral glycosphingolipids isolated from the plerocercoids of a tapeworm, Spirometra erinacei, may be expected to be involved in host-parasite interactions. We have synthesized this glycosphingolipid analogue containing 2-branched fatty alkyl residue in place of ceramide. Glycosylation of nonreducing-end trisaccharide derivative 15 with the reducing-end disaccharide derivative 17 in the presence of trimethylsilyl triflate (TMSOTf) gave the desired oligosaccharide derivative in good yield. The fully per-O-acylated 2-(trimethylsilyl)ethyl glycoside 19 was converted to glycosylimidate 20, which was condensed with 2-(tetradecyl)hexadecanol and subsequently deacylated to give the target glycosphingolipid analogue 22.View full abstractDownload PDF (927K) -
Naoki SAKURA, Katsuro KUROSAWA, Tadashi HASHIMOTO2000 Volume 48 Issue 8 Pages 1166-1170
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTo examine the role of both Arg residues at positions 5 and 7 of dog neuromedin U-8 (d-NMU-8; pGlu1-Phe-Leu-Phe-Arg5-Pro-Arg7-Asn8-NH2) for smooth muscle contractile activity on isolated chicken crop, d-NMU-8 analogs were synthesized where either Arg residue was systematically replaced by various amino acids [X : Ala, Thr, Glu, Gln, Lys, Orn, His, citrulline (Cit) or homoarginine (Har)]. All [X5]-d-NMU-8, except for [Glu5]- and [Des-Arg5]-d-NMU-8, were full agnists, although their affinities to NMU receptors were decreased.No [X7]-d-NMU-8 showed contractile activity even at concentrations of 10-5 mol/l, except for [Har7]-d-NMU-8, which retained weak biological activity. These analogs had no antagonistic activity against porcine neuromedin U-8 (p-NMU-8). The results revealed that Arg7 of d-NMU-8 is indispensable for receptor binding and activation to induce smooth muscle contraction, and the guanidino group of the side chain at position 7, but not at position 5, is strictly recognized by NMU receptors in the chicken crop.View full abstractDownload PDF (811K) -
Satoshi YAMADA, Hiroshi SUEMUNE2000 Volume 48 Issue 8 Pages 1171-1175
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe reactivity of 3-substituted 4-methyl-4-(3-oxobutyl)-2-cyclohexen-1-ones (1) in the presence of a combination of a Lewis acid and a 1, 2-diol was studied. The results suggest several factors that influence 6-membered ring formation, including two types of intramolecular aldol reaction and intramolecular 1, 4-addition, due to the C3-substituent, Lewis acid, and the presence of diol. In this study, novel methodology to prepare two types of decalin skeleton could be developed.View full abstractDownload PDF (818K) -
Masako NOZAWA, Yumiko MURAKAMI, Keiko NODA, Ryouko TAMATSUKURI, Keisuk ...2000 Volume 48 Issue 8 Pages 1176-1186
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSEnzymatic monobenzoylation of (±)-2-hydroxy-decahydro-5, 5, 8a-trimethyl-1-naphthalenemethanol derivatives (1-4) using vinyl benzoate in organic solvent gave the optically active diols (1-4) and monobenzoates (16-19). The enantiomeric excess (ee) of the enzymatic reaction products were found to be in the range of 11% to 49%. On the other hand, enzymatic hydrolysis of the acetoxybenzylidene acetal (±)-25d, e was found to give more than 90% ee of (10aS)-25d, e in moderate yield. Finally, the 90% ee of (10aS)-25e was converted to the 90% ee of the desired (8aS)-1.View full abstractDownload PDF (1599K) -
Motohiko UKIYA, Toshihiro AKIHISA, Shigeyasu MOTOHASHI, Ken YASUKAWA, ...2000 Volume 48 Issue 8 Pages 1187-1189
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe Δδ(δS-δR) values for the C-1 methyl 1H signals in the 1H-NMR spectroscopy of the bis-MTPA esters of four synthetic stereoisomers of alkane-6, 8-diols, viz., bis-MTPA esters of (6S, 8R)-C27- (1a) and C29- (3a) (Δδ=-0.05 ppm), (6R, 8S)-C27- (2a) and C29- (4a) (Δδ=+0.05 ppm), (6S, 8S)-C27- (5a) (Δδ=-0.01 ppm), and (6R, 8R)-C27- (6a) (Δδ=+0.01 ppm) alkane-6, 8-diols, made it possible to differentiate unequivocally among the four stereoisomers. This allowed the determination of the (6S, 8R)-stereochemistry (Δδ=-0.05 ppm for the bis-MTPA esters) for the natural C27- and C29-alkane-6, 8-diols isolated from the flowers of three Compositae plants, Carthamus tinctorius, Cynara cardanclus, and Taraxacum platycarpum.View full abstractDownload PDF (544K) -
Hideyuki ITO, Takashi MURANAKA, Kazuko MORI, Zhe-Xiong JIN, Harukuni T ...2000 Volume 48 Issue 8 Pages 1190-1195
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo new ichthyotoxic compounds, aspidin PB (8) and dryofragin (9), along with three known phloroglucinol derivatives (1-3) and five terpenoids, were isolated from the whole herbs of Dryopteris fragrans by toxicity-directed fractionation using Oryzias latipes (Japanese name; medaka). The structures of the new compounds were determined by spectroscopic methods including 2D NMR techniques. Amongst the isolates, aspidin PB (8), dry-ofragin (9), and 1-5 exhibited potent ichthyotoxic activity against medaka with a median tolerance limit (TLm after 24 h) of 1.2-4.3 μg/ml. These compounds which are toxic to fish also had a potent inhibitory effect on the activation of Epstein-Barr virus early-antigen (EBV-EA) induced by tetradecanoyl phorbol 13-acetate, which is an in vitro short-term assay for anti-tumor promoting agents. Aspidin BB (2) and albicanol (4), which exhibited strong inhibitory effects on the EBV-EA activation, significantly suppressed an in vivo two-stage carcinogenesis on mouse skin.View full abstractDownload PDF (947K) -
Hatsuo MAEDA, Nagomi HINO, Yuji YAMAUCHI, Hidenobu OHMORI2000 Volume 48 Issue 8 Pages 1196-1199
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSReactions of Grignard reagents with bis-phosphonium or mono-phosphonium ions in situ generated from Bu3P and ClCO(CH2)nCOCl (5) or ClCO(CH2)nCO2Et (13) as a tool for preparation of symmetrical diketones or ketoesters were examined. Addition of Bu3P (2.0 eq) to a THF solution of 5 (n=2) at -40°C followed by addition of n-BuMgCl (2.0 eq) gave the corresponding diketone in good yield. When a mixture of Bu3P and the Grignard reagent (2.0 eq each) was added to the dichloride solution at the same temperature, a better result was obtained.The latter method not with PhMgBr but with n-BuMgCl or MeMgBr was shown to be useful for preparation of symmetrical alkanediones and keto alkanoates from various 5 (n=2-6) and 13 (n=2 or 3), respectively. For synthesis of α-diketones or α-ketoesters, only PhMgBr entered the reaction, although the yields were not satisfactory. Addition of a mixture of Bu3P (2.0 eq), MeMgBr (1.0 eq) and BuMgCl (1.0 eq) to a THF solution of 5 (n=4) at -40°C afforded a mixture of 2, 7-undecanedione and the corresponding two symmetrical diketones, with the yield of the unsymmetrical diketone being 36%.View full abstractDownload PDF (704K) -
Takao TANAHASHI, Yukiko TAKENAKA, Naotaka NAGAKURA, Toyoyuki NISHI2000 Volume 48 Issue 8 Pages 1200-1204
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPhytochemical study of the stems of Jasminum nudiflorum has led to the isolation of five new secoiridoid glucosides, jasnudiflosides D (1) and E (2) and nudiflosides A-C (3-5). The structures of these compounds were elucidated on the basis of chemical and spectroscopic evidence.View full abstractDownload PDF (686K) -
Susumu YAMATO, Masaharu NAKAJIMA, Nozomi KAWAKAMI, Kenji SHIMADA, Eiic ...2000 Volume 48 Issue 8 Pages 1205-1207
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe degradation phenomenon of maleate moiety of chlorpheniramine maleate in solution has been demonstrated by means of a peculiar ion-pair HPLC method developed by the authors, which permits the simultaneous determination of chlorpheniramine and maleate. A commercial cough drug containing chlorpheniramine maleate was dissolved in water with m-hydroxybenzoic acid as an internal standard, and then kept for several days at room temperature. It was recognized that the maleate content in the drug solution had gradually decreased, whereas chlorpheniramine content had not decreased. A simple solution of maleic acid was also kept for several days at room temperature, and it was also recognized that the maleate content in the solution preserved at the same concentration as the solution of the commercial cough drug had gradually decreased, and the percent of remaining maleate reached zero. The degraded peaks on HPLC chromatogram were not detected at all by UV detector, and the disappearance of maleate was ascertained by GC-MS. No detectable example of maleate of chlorpheniramine maleate in a commercial cough syrup has suggested that maleate moiety of chlorpheniramine maleate decomposed to carbon dioxide.View full abstractDownload PDF (546K) -
Shu-ichi FUKUYOSHI, Takashi OOI, Takenori KUSUMI2000 Volume 48 Issue 8 Pages 1208-1210
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn SN2 reaction (NaI) of 1, 7-di(methanesulfoxyl)heptadien-4-yl methoxy-(2-naphthyl)acetate and a tributyltin hydride reduction of 1, 7-diiodo-4-yl methoxy-(2-naphthyl)acetate (2NMA) is crucial for determination of the absolute configuration of secondary alcohols.View full abstractDownload PDF (523K) -
Yueh-Hsiung KUO, Chi-I CHANG2000 Volume 48 Issue 8 Pages 1211-1214
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSix new compounds, diospyrolide (1), diospyrolidone (2), diethyl (2R)-malate (3), 3-(E)-coumaroylbetulin-28-yl ethyl nonanedioate (4), 3-(E)-coumaroylbetulin-28-yl ethyl succinate (5), and 3-(E)-coumaroylbetulin-28-yl ethyl (2R)-2-hydroxysuccinate (6), have been isolated from the heartwood of Diospyros maritima. Compounds 1 and 2 are novel trinorlupanes, and 4, 5 and 6 are lupane derivatives. Their structures were determined using spectral and chemical methods.View full abstractDownload PDF (615K) -
Masao NAGAOKA, Michiko ENDO, Mitsuteru NUMAZAWA2000 Volume 48 Issue 8 Pages 1215-1218
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS16α-Hydroxy-17-keto steroids, 1, 3, and 8, and their 17β-hydroxy-16-keto isomers, 4, 5, and 9, were transformed into the corresponding 17β-alkoxy-16-keto derivatives on treatment with trimethylsilyl iodide (TMSI) in the presence of alkyl alcohol in CHCl3 in poor to high yields.View full abstractDownload PDF (654K) -
Ryoko GONDA, Tadahiro TAKEDA, Toshiyuki AKIYAMA2000 Volume 48 Issue 8 Pages 1219-1222
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFive new xanthones, 1, 3, 6-trihydroxy-5-methoxy-4-prenylxanthone (1), 1, 3, 5-trihydroxy-6-methoxy-2-prenylxanthone (2), 1, 3, 5-trihydroxy-4-(3-hydroxy-3-methylbutyl) xanthone (3), 1, 3, 6-trihydroxy-4-prenylxanthone (4), 3, 6-dihydroxy-1, 5-dimethoxyxanthone (5) and one new flavonoid, 3, 5, 7, 4'-tetrahydroxy-2'-methoxyflavone (6) along with seven known xanthones and seven known flavonoids were isolated from the bark of Anaxagorea luzonensis A. GRAY and their chemical structures were determined by means of chemical and spectral studies. Almost all flavonoids and one xanthone (13) showed antioxidant activity.View full abstractDownload PDF (660K) -
Jian-Chen LI, Masateru ONO, Toshihiro NOHARA2000 Volume 48 Issue 8 Pages 1223-1225
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree new oligosaccharide esters named telephioses A-C, were isolated from Polygala telephioides WILLD. and their structures were characterized by spectroscopic data.View full abstractDownload PDF (386K) -
Ryoji KASAI, Kazumasa HARA, Rumiko DOKAN, Noriko SUZUKI, Tohru MIZUTAR ...2000 Volume 48 Issue 8 Pages 1226-1227
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIncubation of ginseng sapogenins with microsomes from rat liver resulted in formation of their 20, 24-epoxides as major metabolites. Identification of the metabolites was performed by HPLC, FAB-MS and EI-MS.View full abstractDownload PDF (400K) -
Jing HUANG, Yukio OGIHARA, Ryoko GONDA, Tadahiro TAKEDA2000 Volume 48 Issue 8 Pages 1228-1229
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree new biphenyl ether lignans, 1, 2 and 3, were isolated from the rhizomes of Curcuma chuanyujin along with curcuminoid compounds 4, 5 and 6 and their chemical structures were determined to be 1-feruloyloxy-2-methoxycinnamic acid, 1-feruloyloxy cinnamic acid and (1-p-hydroxycinnamoyl) cinnamic acid by means of spectral evidence. The latter three known substances showed antioxidant activity.View full abstractDownload PDF (464K) -
Kengo MIYOSHI, AKira OTAKA, Midori KANEKO, Hirokazu TAMAMURA, Nobutaka ...2000 Volume 48 Issue 8 Pages 1230-1233
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new practical strategy has been developed for the synthesis of long-chain phosphopeptide. Both the 2-chlorobenzyloxycarbonyl (ClZ) group for Lys and methyl (Me) for phosphoamino acids remained intact, while other commonly used side-chain protecting groups were cleaved quantitatively, during the reaction using a highly acidic trifluoromethanesulfonic acid (TFMSA)-based reagent system (High TFMSA : TFMSA-TFA-m-cresol=1 : 9 : 1, v/v). Selective deprotection of the ClZ and Me group-containing protected phosphopeptide resin with the High TFMSA gave a partially protected phosphopeptide fragment suitable for thioester-mediated fragment condensation. A deprotection protocol of the 9-fluorenylmethyloxycarbonyl (Fmoc) group, which evades significant side reaction toward the protected phosphoamino acid, was also developed. These two new findings enabled us to synthesize long-chain phosphopeptide via thioester-mediated fragment condensation.View full abstractDownload PDF (693K) -
Yoshio TAKEDA, Kazumi YANAGIHARA, Toshiya MASUDA, Hideaki OTSUKA, Gish ...2000 Volume 48 Issue 8 Pages 1234-1235
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new labdane type diterpenoid, marrubiglobosin, was isolated from the aerial parts of Marrubium globosum ssp. globosum together with the known diterpenoids, marrubiin and marrubinone B. The structure of this new compound was elucidated by spectral methods.View full abstractDownload PDF (441K) -
Yoshihito OHBA, Miyuki SAKATA, Kiyoshi ZAITSU2000 Volume 48 Issue 8 Pages 1236-1238
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTo develop a sensitive and selective chemiluminometric method for the determination of methylglyoxal, we used 2-aminonicotinic acid as the chemiluminescence derivatization reagent. 2-Aminonicotinic acid reacts with methylglyoxal in an acidic solution at 37°C for 4 h and gave a chemiluminescence in N, N'-dimethylformamide containing sodium tert-butoxide. The detection limit (blank intensity plus three-times its standard deviation of methylglyoxal) for methylglyoxal is 233 fmol in the reaction mixture.View full abstractDownload PDF (521K) -
Yan LI, Meselhy R. MESELHY, Li-Quan WANG, Chao-Mei MA, Norio NAKAMURA, ...2000 Volume 48 Issue 8 Pages 1239-1241
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAfter anaerobic incubation of abrusin 2"-O-β-D-apioside (1) with a human fecal suspension, five metabolites were isolated and identified as abrusin (2), 1-(2', 6'-dihydroxy-3', 4'-dimethoxyphenyl)-3-(4"-hydroxyphenyl)-propan-1-one (5), 5, 6-dimethoxybenzene-1, 3-diol (6), 3-(4'-hydroxyphenyl)propionic acid (7) and 3-phenylpropionic acid (8). However, methyl ether derivatives of abrusin (4'-O-methylabrusin and 4'-O-, 5-O-dimethylabrusin) resisted degradation under the same conditions.View full abstractDownload PDF (559K) -
Sam Sik KANG, Young Soo CHANG, Ju Sun KIM2000 Volume 48 Issue 8 Pages 1242-1245
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo new acylated flavonol glycosides, named amurenosides A and B, together with quercetin 3-(2, 6-di-O-α-rhamnopyranosyl-β-galactopyranoside), have been isolated from the whole plant of Vicia amurensis. Their structures were elucidated as quercetin 3-O-α-L-(3-feruloylrhamnopyranosyl)(1→6)-[α-L-rhamnopyranosyl(1→2)]-β-D-galactopyranoside and quercetin 3-O-α-L-(2-feruloylrhamnopyranosyl)(1→6)-[α-L-rhamnopyranosyl(1→2)]-β-D-galactopyranoside on the basis of various NMR techniques, FAB mass spectrometry and chemical reactions.View full abstractDownload PDF (592K) -
Masahiko TANIGUCHI, Yong-Qing XIAO, Kimiye BABA2000 Volume 48 Issue 8 Pages 1246-1247
Published: August 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree novel cyclospirobifuranocoumarins, cyclorivulobirins A-C (1-3), were isolated from the underground part of Pleurospermum rivulorum. They are characterized as three stereoisomers having a different configuration at the C-2 and C-2' position resulting from the condensation of two heraclenol units, respectively, on the basis of chemical and spectral methods.View full abstractDownload PDF (359K)
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