All issues
Volume 45, Issue 11
Displaying 1-28 of 28 articles from this issue
- |<
- <
- 1
- >
- >|
-
Hatsuo MAEDA, Haruka ASHIE, Toshihide MAKI, Hidenobu OHMORI1997 Volume 45 Issue 11 Pages 1729-1733
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn improved method for the transformation of keto acids into cyclic α-hydroxy ketones, induced by the electrochemical generation of a novel acyl anion equivalent from the carboxy group, has been developed. Both five- and six-membered rings were constructed by constant-current electrolysis of δ- and ε-keto acids in the presence of Bu3P using an undivided cell equipped with a graphite anode and a Pt cathode. Attempts to prepare four- and seven-membered ring carbocycles were unsuccessful. The electrochemical reaction was found to be highly stereoselective when cyclization took place onto cyclopentanone and substituted cyclohexanone rings. Stereochemical aspects of the formation of bicyclic products, especially those having a bicyclo[4.3.0]skeleton, are discussed.View full abstractDownload PDF (859K) -
Keizo MATSUO, Masakatsu MORITA, Ken-ichi KAWASHIMA1997 Volume 45 Issue 11 Pages 1734-1738
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA key intermediate for the synthesis of (+)-grandisol, (4aR, 6aR)-4a-methyl-2-oxabicyclo[4.2.0]octan-1-one, was synthesized starting from (-)-quinic acid as the chiral source.View full abstractDownload PDF (867K) -
Yasuoki MURAKAMI, Toshiko WATANABE, Hideharu SUZUKI, Nobuyo KOTAKE, To ...1997 Volume 45 Issue 11 Pages 1739-1744
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn the Hemetsberger-Knittel reaction for indole synthesis, the intermediate ethyl 2-azido-3-hydroxy-3-aryl-propionate (4) was found to be formed in the reaction of arylaldehyde 1 with ethyl azidoacetate at a lower temperature (-30°C) as the main product, while only ethyl 2-azidocinnamate (2) is known to be formed at a higher temperature (0°C). It was also found that fluoride ion was effective for obtaining 4. Compound 4 was converted to 2 in good yield by treatment with SOCl2/pyridine or SOCl2/Et3N. A trial application of this reaction to ketone is also described.View full abstractDownload PDF (843K) -
Machiko ONO, Norio YOSHIDA, Hiroyuki AKITA1997 Volume 45 Issue 11 Pages 1745-1750
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo piericidin analogues having a simple aromatic ring were synthesized based on a palladium-catalyzed cross-coupling reaction and the reaction of sulfone and aldehyde by the Julia coupling procedure. The reaction of 3-methoxyphenyl-tri-n-butyltin (8) and a mixture of allylic chlorides ((E)-9 and (Z)-10) in the presence of tetrakis(triphenylphosphine) palladium(0) afforded a mixture of 5-arylacetals (E)-11 and (Z)-12. The coupling reaction of the non-conjugated aldehyde (E)-13 or (Z)-14 prepared from the 5-arylacetal (E)-11 or (Z)-12 and the sulfone 4 provided (2E)-19 or (2Z)-20. Benzoylation of (2E)-19 or (2Z)-20 followed by reductive olefin-formation with sodium amalgam gave the piericidin analogue (2E)-1 or (2Z)-2. Analogue (2E)-1 has the same side chain as natural piericidin and analogue 2 is the (2Z)-isomer of analogue 1 at the side chain.View full abstractDownload PDF (829K) -
Takashi TANAKA, Nobuko UEDA, Hideo SHINOHARA, Gen-ichiro NONAKA, Isao ...1997 Volume 45 Issue 11 Pages 1751-1755
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn the course of studies on polyphenol metabolism in wood, four new C-glycosidic ellagitannins named castacrenins D-G were isolated from the wood of the Japanese chestnut tree (Castanea crenata). Castacrenins D and F are related to vescalagin and have a gallic acid and an ellagic acid moiety, respectively. Castacrenins E and G are oxidative metabolites of castacrenins D and F, respectively, in which a pyrogallol ring of each C-glycosidic ellagitannin unit is replaced by a cyclopentenone ring.View full abstractDownload PDF (726K) -
Takaaki ISHIZUKA, Yasunori YAOITA, Masao KIKUCHI1997 Volume 45 Issue 11 Pages 1756-1760
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFour new sterols, 5α, 6α-epoxy-(22E, 24R)-ergosta-8(14), 22-diene-3β, 7β-diol (1), (22E, 24R)-ergosta-8, 22-diene-3β, 5α, 6β, 7α-tetrol (2), (22E, 24R)-ergosta-7, 9(11), 22-triene-3β, 5α, 6β-triol (3) and 3β, 5α, 6β-trihydroxy-(22E, 24R)-ergost-22-en-7-one (4), have been isolated from the fruit bodies of Grifola frondosa (FR.) S. F. GRAY (Polyporaceae)together with fourteen known ones (5-18), of which two (5 and 6) are reported for the first time from a natural source. The structures of these compounds were elucidated on the basis of spectral data.View full abstractDownload PDF (790K) -
Naoto UEYAMA, Shyuichi WAKABAYASHI, Tsuyoshi TOMIYAMA1997 Volume 45 Issue 11 Pages 1761-1766
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSKT-362 (5-[3-[2-(3, 4-Dimethoxyphenyl)ethyl]aminopropionyl]-2, 3, 4, 5-tetrahydro-1, 5-benzothiazepine fumarate) is an intracellular Ca2+ antagonist. The compound obtained by introducing methyl groups onto the nitrogen (R2) of the side chain of KT-362 showed vasoconstrictive activity. Therefore we synthesized various derivatives, and examined their activities. Substitution at position R2 of the side chain resulted in potent contractile activity, and the optimal alkyl length was to or three carbons. The potency was further increased by the introduction of a chloro group at the R1 position of 2, 3, 4, 5-tetrahydro-1, 5-benzothiazepines. One of the synthesized compounds, 8-chloro-5-{N-ethyl-N-[2-(3, 4-dimethyoxyphenyl)ethyl]aminopropionyl}-2, 3, 4, 5-tetrahydro-1, 5-benzothiazepine fumarate (9b), showed an EC50 value of 3.47×10-8 M for contraction of rabbit iliac artery. The action of compound 9b was antagonized competitively by an H1-histamine receptor antagonist, diphenhydramine, and the pA2 value was 7.82. The maximum constriction was inhibited by a Ca2+ entry blocker, nicardipine, but not by an α1-adrenoreceptor antagonist, prazosin. In a Ca2+-free medium, tonic constriction induced by 9b disappeared, and only a phasic constriction was oberved. Though this phasic constriction was inhibited by diphenhydramine, it was not inhibited by prazosin or nicardipine.View full abstractDownload PDF (751K) -
Masaya KATO, Keiko KOMODA, Akira NAMERA, Yusuke SAKAI, Satoshi OKADA, ...1997 Volume 45 Issue 11 Pages 1767-1776
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of pyrrole butyric acid derivatives was synthesized and evaluated for inhibitory activity on human and rat steroid 5α-reductase in vitro and ex vivo. 3-Benzoyl-4-alkylpyrrole-1-butyric acids and 1-methyl-2-alkyl-3-benzoylpyrrole-5-butyric acid derivatives were effective inhibitors. Structure activity relationships were evaluated among the 37 compounds synthesized. Compound 37 (HQL-1069) shows potent inhibitory activities against both rat and human 5α-reductase.View full abstractDownload PDF (1412K) -
Shorong-Shii LIOU, Yue-Ling ZHAO, Ya-Ling CHANG, Che-Ming TENG, Cherng ...1997 Volume 45 Issue 11 Pages 1777-1781
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn a serach for inhibitors of platelet aggregation, some α-methylene-γ-butyrolactones bearing 2-methylquinoline and 8-hydroxyquinoline moieties were synthesized and evaluated for antiplatelet activities against thrombin (Thr)-, arachidonic acid (AA)-, collagen (Col)-, and platelet-activating factor (PAF)- induced aggregation in washed rabbit platelets. With the exception of 2-[[2, 3, 4, 5-tetrahydro-4-methylene-5-oxo-2-(4-phenylphenyl)-2-furanyl]methoxy]-8-hydroxyquinoline (8f), these α-methylene-γ-butyrolactones completely inhibited the platelet aggregation induced by AA and Col. The 2-methylquinoline derivatives were also active against Thr- and PAF-induced aggregation, while their 8-hydroxyquinoline counterparts were relatively inactive.View full abstractDownload PDF (952K) -
Kouki KITAGAWA, Noriko MIZOBUCHI, Teruo HAMA, Tohru HIBI, Ryoji KONISH ...1997 Volume 45 Issue 11 Pages 1782-1787
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSBased on the physicochemical and pharmacological properties of drugs having an adamantane skeleton, an adamantane-based moiety was evaluated as a drug carrier for poorly absorbed compounds, including peptides, active towards the central nervous system (CNS). Seven [D-Ala2]Leu-enkephalin derivatives conjugated with an adamantane-based moiety at the C-terminus or N-terminus were prepared by the solution-phase method and their biological activities were examined. The compounds derivatized at the C-terminus through an ester or amide linkage were much more lipophilic than the parent peptide and exhibited moderate in vitro opioid activity (guinea-pig ileum assay). Among them, four derivatives (1, 2, 4, 5), exhibited significant antinociceptive effects in an in vivo assay (mouse tail-pressure test) after subcutaneous administration. This result suggests that the introduction of the lipophilic adamantane moiety into [D-Ala2]Leu-enkephalin would improve the permeation of the poorly absorbed parent peptide through the blood-brain-barrier (BBB) withoug loss of antinociceptive effect.View full abstractDownload PDF (952K) -
Mitsuko MAEDA, Yasuhiro IZUNO, Koichi KAWASAKI, Yoshihisa KANEDA, Yu M ...1997 Volume 45 Issue 11 Pages 1788-1792
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSHybrids of a fibronectin-related peptide[Arg-Gly-Asp (RGD)] with poly(ethylene glycol) (PEG) analogs were prepared by a simple and easy procedure. Two amino-PEG analogs were used as carriers for hybrid formation of the RGD. One was poly(oxyethylene)dipropylamine and the other was Jeffamine ED type, which has branched chains. RGD peptides were formed stepwise on PEG analogs by the diisopropylcarbodiimide method. The synthetic intermediates were easily purified by molecular-sieve gel chromatography and the final products were purified by molecular-sieve gel chromatography, followed by HPLC. This simple and easy preparation procedure using molecular-sieve gel chromatography for purification of synthetic intermediates is advantageous for the preparation of peptide-polymer hybrids. We found that PEG is stable to HF treatment at 0°C for 1 h. The inhibitory effect of the RGD hybrids on experimental metastasis of B16-BL6 was examined in mice. The Jeffamine type hybrid showed no inhibitory effect at the dose of 1 mg/mouse, but poly(oxyethylene)dipropylamine type hybrid was inhibitory at the same dose. The effect of the latter hybrid was about the same as that of 1 mg of RGD. One mg of the hybrid contains 0.18 μmol of RGD and 1 mg of RGD is 2.38 μmol. Thus it can be said that the inhibitory effect of RGD was potentiated by hybrid formation with poly(oxyethylene)diisopropylamine.View full abstractDownload PDF (790K) -
Kouichi UOTO, Satoru OHSUKI, Haruhiro TAKENOSHITA, Takashi ISHIYAMA, S ...1997 Volume 45 Issue 11 Pages 1793-1804
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTo investigate the role of the 2'-hydroxy group at the C-13 side chain of docetaxel in the antitumor activity, we prepared several 2', 2'-difluoro derivatives of docetaxel and evaluated their cytotoxicity against mouse leukemia and human tumor cell lines and their microtubule disassembly-inhibitory activity. These analogues were prepared by esterification of protected 10-deacetylbaccatin III (21) with appropriate α, α-difluorinated carboxylic acids (Charts 1 and 2). Among these 2', 2'-difluorodocetaxel derivatives, 2', 2'-difluorodocetaxel (23b) was approximately 3-10 times as active as 2'-fluorodocetaxel (29a) in terms of cytotoxicity. In addition, the 3'-(2-furyl) (23h) and 3'-(2-pyrrolyl)(23p) analogues showed activity comparable or superior to that of docetaxel (2).View full abstractDownload PDF (1760K) -
Toshihiko TASHIMA, Hiroyuki KAGECHIKA, Motonori TSUJI, Hiroshi FUKASAW ...1997 Volume 45 Issue 11 Pages 1805-1813
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSeveral polyenylidene thiazolidinedione or 2-thioxo-4-thiazolidinone derivatives were synthesized and their retinoidal activities were examined in terms of the differentiation-inducing ability towards human promyelocytic leukemia HL-60 cells and inhibitory effect on interleukin (IL)-1α-induced IL-6 production in MC3T3-E1 cells.Compounds containing a trimethylcyclohexenyl ring induced HL-60 cell differentiation with weaker activity than retinoic acid (1a) by one or two orders of magnitude. The thiazolidinedione derivatives (2, 5, 7) showed stronger activity than the corresponding 2-thioxo-4-thiazolidinone derivatives (3, 6, 8). The effects of a retinoid antagonist(LE540) and synerists (retinoid X receptor (RXR) agonists, HX600 or HX630) on the activities of thiazolidine derivatives indicate that these compounds elicit their activities through the nuclear retinoic acid receptors (RARs).All the thiazolidines examined also inhibited IL-1α-induced IL-6 production with IC50 values of 10 nM order. The retinoidal activities of the thiazolidines are significant, considering that replacement of the carboxylic acid in retinoid structures with bioisosteric functional groups is generally ineffective, as seen in the structure-activity relationships of retinoidal benzoic acids.View full abstractDownload PDF (1352K) -
Akira SHIRAHATA, Masanori YOSHIOKA, Zenzo TAMURA1997 Volume 45 Issue 11 Pages 1814-1819
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn the belief that endogenous 1, 2, 3, 4-tetrahydro-6, 7-dihydroxyisoquinoline (DA-Fp) could be a potential marker involved in the etiology of various diseases such as Parkinsonism, we attempted to develop a fluorescence method for DA-Fp. It was synthesized by condensation of dopamine with formaldehyde according to an established method.Periodate was identified by screening from various oxidation reagents as a fluorescence reagent to DA-Fp. Optimal reaction conditions were obtained with 0.25 mM NaIO4 in 0.1 M phosphate buffer (pH 8.0) at 37°C for 15 min. The fluorescence spectrum of the derivative showed that we had found a new reaction specific for DA-Fp. This reaction we coupled on-line to high performance liquid chromatography (HPLC), which enabled us to achieve a highly sensitive method for determining DA-Fp. A working curve was linear from 2 to 800 pmol of DA-Fp per injection.To determine DA-Fp in biological materials, the pretreatment before HPLC was optimized by hydrolysis of its conjugate and suppression of the artifact with l-phenylephrine. Urinary excretion of DA-Fp in men was measured by this new present method. The urinary excretion of endogenous DA-Fp increased in a rabbit given L-DOPA. The DA-Fp concentration was determined in rat brain. The significance of DA-Fp in these biological materials is discussed and evaluated. We conclude that the present method will be useful for studying tetrahydroisoquinolines involved in meny diseases.View full abstractDownload PDF (988K) -
Kazuichi HAYAKAWA, Akio NAKAMURA, Noriko TERAI, Ryoichi KIZU, Kyoko AN ...1997 Volume 45 Issue 11 Pages 1820-1822
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSDiesel exhaust particulates were extracted with benzene-ethanol (3 : 1, v/v) and separated into five fractions by silica-gel column chromatography. Direct-acting mutagenic activity was assayed by the Ames test using the Salmonella typhimurium YG1024 strain. The total activity of five fractions was about four times greater than that of the crude extract, suggesting that the activities in the fractions were suppressed in the crude extract. Strong activity was observed in fraction 4 which was eluted with dichloromethane (61.5% of the total activity) and fraction 5 which was eluted with ethanol (35.3%). Nitropolycyclic aromatic hydrocarbons (NPAHs) were determined by high-performance liquid chromatography with chemiluminescence detection. They were found mainly in fraction 4, although one NPAH was in fraction 3 which was eluted with n-hexane-dichloromethane (3 : 1, v/v). Based on these results, 53.1% of the activity in fraction 4 was attributed to NPAHs. The contribution of 1-nitropyrene and 1, 3-, 1, 6- and 1, 8-dinitropyrenes was great and that of the other NPAHs was small. The mutagenic compound in fraction 5 was not identified. Fractions 1 and 2, which were eluted with n-hexane, and fraction 3 suppressed the activity of fraction 4. Polycyclic aromatic hydrocarbons in fractions 2 and 3 were considered as possible suppressors of NPAHs.View full abstractDownload PDF (583K) -
Koji HASE, Jianxin LI, Purusotam BASNET, Quanbo XIONG, Shuichi TAKAMUR ...1997 Volume 45 Issue 11 Pages 1823-1827
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe n-BuOH extract of Swertia japonica showed a significant hepatoprotective effect on D-galactosamine(D-GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. The activity-guided fractionation led to the isolation of a new tetrahydroxanthone derivative, tetrahydroswertianolin (1), as well as two known iridoids, gentiopicroside (2) and sweroside (3). Their structures were elucidated by spectroscopic methods and chemical reactions. Of the three compounds, 2 and 3 possessed mild hepatoprotective activity at a dose range of 25-50 mg/kg, whereas, 1 exhibited potent activity in a dose-dependent manner. The hepatoprotective effect of tetrahydroswertianolin (1) was stronger than that of glycyrrhizin which was used as a positive control.View full abstractDownload PDF (855K) -
Tetsu MORIMURA, Kaoru KOHNO, Yoshifumi NOBUHARA, Hayashi MATSUKURA1997 Volume 45 Issue 11 Pages 1828-1832
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe photoreaction of orbifloxacin (ORFX), a fluoroquinolone derivative having a fluorine at the 8 position, was investigated in aqueous solution containing chloride ion to determine its photochemical properties. In the presence of chloride ion, ORFX was found to convert into a photoproduct substituted by chlorine at the 8 position (8-Cl ORFX) under irradiation by ultraviolet-A (UVA) light. Although the formation rate of 8-Cl ORFX increased greatly with increase in chloride ion concentration, the apparent photodegradation rate of ORFX in aqueous solution was not varied by the presence of the ion. This implies that the dissociation of the C-F bond at the 8 position is the rate-limiting steps in the photodegradation of ORFX. The active oxygen generated by the photosensitization of ORFX were determined by measuring the bleaching rate of p-nitrosodimethylaniline and the reduction rate of cytochrome c. Their generation was inhibited by sodium azide and superoxide dismutase but not by D-mannitol.The photoreaction between ORFX and chloride ion also inhibited their generation. The mechanism is believed to be the photochlorination at the 8 position competing with the reaction between free radical and oxygen.View full abstractDownload PDF (690K) -
Toru MAEJIMA, Takashi OSAWA, Kingo NAKAJIMA, Masao KOBAYASHI1997 Volume 45 Issue 11 Pages 1833-1839
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFactors affecting granulatabilities in the tumbling melt granulation (TMG) method for the preparation of spherical beads without using any solvent were investigated. Beads of ten kinds of non-meltable materials were prepared using hydrogenated rape oil (HRO) as binder by changing the mixing ratio of the meltable material (XM), and the recovery percent (Rec%) and yield percent (Ysc%) of the non-agglomerated core beads were evaluated. In all the powders, both Rec% and Ysc% were excellent with choice of the optimum mixing ratio (Xop), suggesting the great advantage of this method. The values of liquid saturation of the coated layer (φ) at Xop were calculated as around 0.4 in bisbentiamine, cornstarch, lactose, talc, titanium dioxide, and zinc oxide; and around 0.6 in the four cellulose derivatives. The high values in cellulose derivatives could be due to the penetration of the meltable materials into these powders. Thus, Xop seemed to be determined in ordinary powders by choosing XM which would give the φ value of 0.4. The granulatability became worse as the viscosity of the meltable material increased, but the wettability evaluated by the liquid penetration method did not have much effect on the granulatability, in contrast with the wet granulation. From these results, the difference in the granulating mechanism between TMG and wet granulation was discussed.View full abstractDownload PDF (1141K) -
Kazumi DANJO, Tsuyoshi NAKATA, Akinobu OTSUKA1997 Volume 45 Issue 11 Pages 1840-1844
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSEthenzamide (ETZ) solid dispersions were prepared using the sugars sucrose, maltose, galactose and mannitol as carriers by melting and rapid cooling with liquid nitrogen. The physical characteristics of these solid dispersions were investigated by powder X-ray diffraction, differential scanning calorimetry and dissolution rate analyses. The dissolution rate of ETZ can be significantly increased by decreasing the crystallinity of ETZ in solid dispersions.The maximum dissolution rate was observed with solid dispersions containing sucrose, and X-ray diffraction analysis suggested that ETZ was present in a totally amorphous state.The physical stability of amorphous sugars in dispersions prepared by rapid cooling was also investigated. Solid dispersions made with amorphous sucrose were more stable than those with other sugars. These results indicated that amorphous sucrose is useful as a carrier for production of solid dispersions.View full abstractDownload PDF (642K) -
Hiroyuki TOKUMITSU, Yoshinobu FUKUMORI, Yuko TSUDA, Yoshio OKADA, Fumi ...1997 Volume 45 Issue 11 Pages 1845-1850
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe stability of tert-butoxycarbonyl-Tyr-Leu-Val-CH2Cl (YLV) with inhibitory effect of human leukocyte elastase was investigated in aqueous solution, α-chymotrypsin solution and biological media. In all cases studied here, the degradation was observed as a pseudo-first order reaction. The half-life for the degradation of YLV in an aqueous solution of pH 7.4 at 37°C was 35.9 h. YLV was most stable at about pH 3.8-5.8 and the effect of temperature was explained by the Arrhenius equation. The activation energies of the degradation in aqueous solutions at pH 2.0, 4.8, and 7.4 were 24.6, 22.1 and 23.4 kcal/mol, respectively. The degradation products in aqueous solution were analyzed by HPLC-MS and were estimated as Boc-Tyr-Leu-Val-CH2OH at pH 7.4 and H2N-Tyr-Leu-Val-CH2Cl at pH 2.0. In a bovine pancreas α-chymotrypsin solution at 37°C, the half-life and YLV was 15 min at 25.6 μg/ml of α-chymotrypsin solution. In the rat plasma, the half-life of YLV was 42.4 min (YLV 26.7 μg/ml plasma), and in rat liver, lung and spleen homogenates, the degradation rate constants of YLV were 37.6, 10.3 and 23.5 times larger than that in plasma solution, respectively (all fluids containing 5 mg protein/ml).YLV was less stable than nafarelin acetate, secretin, adrenocorticotropic hormone (ACTH) and gonadorelin in an aqueous solution of pH 7.4.View full abstractDownload PDF (904K) -
Hidetoshi WATANABE1997 Volume 45 Issue 11 Pages 1851-1855
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTo elucidate the differences in the antioxidant potency of troglitazone and α-tocopherol in the oxidation of low density lipoprotein (LDL), the structure of the phenoxyl radical of troglitazone and the antioxidant activity of troglitazone in homogeneous solution and liposomal membranes were investigated. The antioxidant activity of troglitazone in homogenous solution based on the cis-parinaric acid fluorescence method was not substantially different from that of α-tocopherol. The ESR study using a spin label technique showed that troglitazone more effectively scavenged the radicals generated in the water phase outside of the liposomal membranes than those generated from the interior of the membranes than did α-tocophenol. These results suggest that the difference in the antioxidant potency of troglitazone and α-tocopherol in the oxidation of LDL is partly due to the mobility and the position of these compounds in the liposomal membrane.View full abstractDownload PDF (770K) -
Tomohiro ENDO, Hiromasa NAGASE, Haruhisa UEDA, Atsushi SHIGIHARA, Shoi ...1997 Volume 45 Issue 11 Pages 1856-1859
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAlthough it has already been found that cyclodextrin glucanotransferase (CGTase) produces cyclodextrins(CDs) composed of six to thirteen glycopyranose units, the existence of CDs which have more than fourteen glycopyranose units has still not been confirmed. Cyclomaltotetradecaose (ι-CD), cyclomaltopentadecaose (κ-CD), cyclomaltohexadecaose (λ-CD) and cyclomaltoheptadecaose (μ-CD) are a new series of large-ring CDs composed of 14-17 α-(1→4)-linked D-glycopyranose units, respectively. ι-, κ-, λ- and μ-CD were purified from the commercially available CD powder produced by CGTase, by a combination of HPLC and column chromatography. The molecular weights of ι-, κ-, λ- and μ-CD were determined by FAB-MS, and their cyclic structures were identified by 1H-NMR and 13C-NMR. The 13C-NMR chemical shifts of ι-, κ-, λ- and μ-CD were elucidated and compared with those of δ-, ε-, ζ-, η- and θ-CD, and their structures were predicted from the results.View full abstractDownload PDF (639K) -
Yoshio OKADA, Noriyuki SHINTOMI, Yukihiro KONDO, Toshio YOKOI, Shima J ...1997 Volume 45 Issue 11 Pages 1860-1864
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA 2-adamantyloxycarbonyl (2-Adoc) group was introduced as a protecting group for the hydroxyl function of tyrosine (Tyr) through the Shotten-Bauman reaction of 2-adamantyloxycarbonyl chloride with the copper complex of Tyr. The 2-Adoc group is stable to trifluoroacetic acid (TFA), 5.0 N HCl/dioxane, hydrogenation over a Pd catalyst and tertiary amine, and is easily removed by treatment with 1 M triflyoromethanesulfonic acid (TFMSA)-thioanisole/TFA and HF. Boc-Tyr(2-Adoc)-OH was prepared by the reaction of (Boc)2O and H-Tyr(2-Adoc)-OH in the presence of triethylamine. Boc-Tyr(2-Adoc)-OH was successfully applied to the synthesis of Boc-Ala-Thr-Val-Lys(2-Adoc)-Phe-Lys(2-Adoc)-Tyr(2-Adoc)-Lys(2-Adoc)-Gly-OH, corresponding to the sequence 1-9 of Sulfolobus solfataricus RNase, and Boc-Tyr(2-Adoc)-Asp(O-2-Ada)-Gly(O-cHex)-Gly-OH, corresponding to the sequence 33-36 of S. solfataricus RNase.Boc-Phe-Lys(2-Adoc)-Tyr(2-Adoc)-Lys(2-Adoc)-Gly-OBzl was treated with anhydrous HF to afford H-Phe-Lys-Tyr-Lys-Gly-OH wighout any side reactions, in a good yield.View full abstractDownload PDF (851K) -
Tokujiro KITAGAWA, Naohiro AKIYAMA1997 Volume 45 Issue 11 Pages 1865-1866
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSDL-3-(2-Furyl)alanine (1) was prepared by the condensation of 2-(bromomethyl)furan (7) with diethyl formamidomalonate (2), followed by the traditional saponification-decarboxylation techniques.View full abstractDownload PDF (360K) -
Taisuke ITAYA, Yasutaka TAKADA, Tae KANAI, Tozo FUJII1997 Volume 45 Issue 11 Pages 1867-1869
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn alternative synthesis of N6, 3, 9-trimethyl-8-oxoadenine (caissarone) (7b) has been accomplished by regio-selective methylation of N6, 3-dimethyl-8-oxoadenine (9-demethylcaissarone) (5b), which was obtained by N(7)-oxidation of N6, 3-dimethyladenine (2b) with m-chloroperoxybenzoic acid followed by O-methylation with MeI and subsequent treatment with aqueous NaOH. The UV spectral data for the dimethylated 8-oxoadenine 5b and eight of its regioisomers, among with the O8, 9-dimethyl isomer 9 was prepared for the first time in the present work, are summarized.View full abstractDownload PDF (553K) -
Akira MATSUHISA, Akihiro TANAKA, Kazumi KIKUCHI, Yoshiaki SHIMADA, Tak ...1997 Volume 45 Issue 11 Pages 1870-1874
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of compounds structurally relate to 4'-[(2, 3, 4, 5-tetrahydro-1H-1-benzazepin-1-yl)carbonyl]benzanilide was synthesized and demonstrated to have arginine vasopressin (AVP) antagonist activity for both V1A and V2 receptors. The introduction of a phenyl or a 4-substituted phenyl group into the ortho position of the benzoyl moiety resulted in an increase in both binding affinity and antagonistic activity. The 2-(4-methylphenyl) derivative (1g) exhibited high antagonistic activities for both V1A (8.6-fold) and V2 (38-fold) receptors and high oral activity (8.6-fold) compared with the 2-methyl lead compound (1a). Datail of the synthesis and the pharmacological properties of this series are presented.View full abstractDownload PDF (758K) -
Keisuke KOJIMA, Keiichiro HATANO, Purev ONDOGNIJ, Binderya MUNAAGIN, Y ...1997 Volume 45 Issue 11 Pages 1875-1876
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom the aerial parts of Solidago dahurica 10β-hydroxy-8β-methoxyeremophilenolide (1) and 8β, 10β-dihydroxy-eremophilenolide (2) have been isolated. The first X-ray crystal structure analysis of 1 has established the absolute configuration of eremophilenolide.View full abstractDownload PDF (395K) -
Tsutomu MORIKAWA, Takuo NARASAWA, Chiseko SAKUMA, Takeo TAGUCHI1997 Volume 45 Issue 11 Pages 1877-1879
Published: November 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIndium-mediated coupling reactions of δ-oxygenated allyl halide derivatives 1 with aldehydes in aqueous media proceeded at the γ-position to give diol derivatives 2. Compound 1 is equivalent to an allylic carbanion 4 with a neighboring oxygen functional group generated in aqueous media.View full abstractDownload PDF (450K)
- |<
- <
- 1
- >
- >|