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Volume 46, Issue 8
Displaying 1-31 of 31 articles from this issue
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Matsutaka HIGA, Kazuhito OGIHARA, Seiichi YOGI1998 Volume 46 Issue 8 Pages 1189-1193
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom the fresh fruits of Diospyros maritima BLUME (Ebenaceae) three new naphthoquinones, 3-bromoplumbagin (1), ethylidene-6, 6'-biplumbagin (2), and 3-(2-hydroxyethyl)plumbagin (3), were isolated, in addition to six known naphthoquinones, 3-chloroplumbagin (4), 3-methylplumbagin (5), plumbagin (6), droserone (7), elliptinone (8), and maritinone (9). The structures of the new compounds were established by chemical and spectroscopic means.The 21 compounds isolated from this plant were examined for ichthyotoxic activity, germination inhibitory activity, and antifugal activity. The naphthoquinone derivatives from the fruits of Diospyros maritima showed a variety of biological activities, especially plumbagin (6), which showed strong activity in these three bioassays.View full abstractDownload PDF (709K) -
Hiroyuki MINAMI, Sayoko ANZAKI, Miwa KUBO, Mitsuaki KODAMA, Kazuyoshi ...1998 Volume 46 Issue 8 Pages 1194-1198
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFive new vibsane-type diterpenes, vibsanin G, vibsanin H, vibsanin K, 18-O-methylvibsanin K and 15, 18-di-O-methylvibsanin H were isoalted from the leaves of Viburnum awabuki (Caplifoliaceae). Their structures were elucidated by analyses of spectroscopic data involving comparison of their 13C-NMR data with those of the previously known vibsanin C, and the structure of vibsanins H and K were confirmed by X-ray crystallographic analysis and chemcial transformation, respectively. All five new compounds differ from the seven-membered ring vibsane-type diterpene, vibsanin C, only in the C-12-C-17 side chain.View full abstractDownload PDF (701K) -
Kiyoshi HORITA, Masaaki NAGASAWA, Youji SAKURAI, Osamu YONEMITSU1998 Volume 46 Issue 8 Pages 1199-1216
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe C16-C36 unit of halichondrin B was stereoselectively synthesized via the aldol condensation of two C16-C26 esters with the previously synthesized C27-C36 aldehyde followed by E ring construction. The C16-C26 esters were prepared starting from (2S)-3-hydroxy-2-methylpropionic acid and L-tartaric acid via construction of the D ring by iodoetherification.View full abstractDownload PDF (2989K) -
Kazuhiro KONDO, Yasuoki MURAKAMI1998 Volume 46 Issue 8 Pages 1217-1219
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSHighly selective benzoylation of a less hindered amino group in the presence of a more hindered amino group with 2-chloro-N, N-dibenzoylaniline (2d), a convenient to use and stable reagent, is described.View full abstractDownload PDF (487K) -
Taisuke ITAYA, Tae KANAI1998 Volume 46 Issue 8 Pages 1220-1224
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn improved synthesis of the key intermediates (3 and 8) for the synthesis of β-hydroxywybutines [[R-(R*, S*)]- and [S-(R*, R*)]-4], the most probable structures for the minor base from rat liver tRNAPhe, has been achieved by the Witting reaction between 1-benzyl-7-formylwye (1) and the phosphorane derived from (R)-2-[(methoxycarbonyl)amino]-3-(triphenylphosphonio)propanoate (10), followed by methylation, OsO4 oxidation, and cyclocondensation with COCl2 in the presence of pyridine. The racemic forms of β-hydroxywybutines [(R*, S*)- and (R*, R*)-4], which were required for the determination of the optical purity of [R-(R*, S*)]- and [S-(R*, R*)]-4 by means of chiral HPLC, were conveniently prepared through pyrolysis of the cyclic carbonate 3 followed by NaBH4 reduction and catalytic hydrogenolysis. The samples of [R-(R*, S*)]- and [S-(R*, R*)]-4 were thus shown to be optically pure.View full abstractDownload PDF (883K) -
Fumiyuki KIUCHI, Noriko SUZUKI, Yumiko FUKUMOTO, Yoshihisa GOTO, Marik ...1998 Volume 46 Issue 8 Pages 1225-1228
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSEmbelin, a major constituent of Embelia ribes BURM. (Myrsinaceae) was transformed into different types of compounds through dimerization during preparation of a decoction. Two of the products are proposed to have furanylidene benzofuranone and 1, 4-dibenzofurandione skeletons on the basis of spectroscopic means. The transformation of embelin in boiling water is markedly accelerated by the presence of fatty acids.View full abstractDownload PDF (751K) -
Fumiyuki KIUCHI, Hiromi TAKASHIMA, Yoshisuke TSUDA1998 Volume 46 Issue 8 Pages 1229-1234
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS2, 5-Dihydroxybenzoquinones, when heated in water, react to form different types of compounds through dimerization. The features of this unique reaction were clarified using a model compound, 2, 5-dihydroxy-3-methyl-benzoquinone. The structures of the products were established by X-ray analysis and spectroscopic means.View full abstractDownload PDF (864K) -
Fumiko ABE, Tatsuo YAMAUCHI, Hirotaka SHIBUYA, Isao KITAGAWA, Masami Y ...1998 Volume 46 Issue 8 Pages 1235-1238
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSeventeen alkaloids were isolated from the air-dried leaves of Alstonia villosa and their structures characterized. One of the seven new alkaloids was elucidated to be (19Z)-5α-methoxyrhazimine, having a 3, 4-dihydroquinoline nucleus.View full abstractDownload PDF (663K) -
Kazuko YOSHIKAWA, Koji MATSUCHIKA, Shigenobu ARIHARA, Hsen-Chang CHANG ...1998 Volume 46 Issue 8 Pages 1239-1243
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe structural elucidation of six new related polyoxypregnane glycosides, gymnepregosides A (1), B (2), C (3), D (4), E (5) and F (6), together with two known compounds, from the roots of Gymnema alternifolium (Asclepiadaceae) was achieved through on a detailed study of 1H- and <13>C-NMR spectral data and chemical means. The results obtained for new compounds, 1-6, show that they are (20S)-pregn-6-ene-3β, 5α, 8β, 12β, 14β, 17β, 20-heptaol or sarcostin 3-O-glycosides, and all the sugars at C-3 are β(1→4)-linked. Some of them possessed benzoyl, cinnamoyl and tigloyl residues as the ester linkages located at C-12 and/or C-20 of the aglycon.View full abstractDownload PDF (748K) -
Hironori FURUKAWA, Kazunori KOIDE, Ken-ichi TAKAO, Susumu KOBAYASHI1998 Volume 46 Issue 8 Pages 1244-1247
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSGlycosylation reactions using a glycosyl 2-pyridinecarboxylate as a glycosyl donor were performed. Glycosyl 2-pyridinecarboxylate was designed based on a variation of the Remote Activation Concept and is activated through bidentate coordination to mild Lewis acids such as copper triflate and tin triflate. This method was effective for the glycosidation of not only glucose, but several other sugars such as the mannose-type, 2-azidosugar-type, and 2-deoxysugar-type. Various disaccharides were obtained in excellent yield by this reaction.View full abstractDownload PDF (604K) -
Kazunori ODASHIMA, Takashi ITO, Koji TOHDA, Yoshio UMEZAWA1998 Volume 46 Issue 8 Pages 1248-1253
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSComplexation of quaternary ammonium salts (Q+X-) and undissociated, neutral phenols (ArOH) in homogeneous organic solutions was systematically investigated to afford a reliable quantitative basis for a new model of anionic potentiometric response to neutral phenols, displayed by organic liquid membranes based on Q+X-. IR, 1H- and 13C-NMR, and UV studies indicated complexation of Q+X- and ArOH in 1 : 1 stoichiometry in nonpolar organic solvents such as benzene and chloroform. The stability constant (Ks) of the complex was affected by the acidity and lipophilicity of the ArOH component as well as the size of X- of the Q+X- component; stronger complexes were formed by ArOH with a lower pKa and higher log Poct, as well as by Q+X- with a smaller ionic radius for X-. These results suggest that the major driving force for complexation is hydrogen bonding interactions between X- and the phenolic OH. The Ks values were found to be parallel with the magnitudes of anionic potentiometric responses by membranes based on Q+X-, indicating that the complexation of ArOH by Q+X- plays an important role in the anionic potentiometric responses. The significance of proton dissociation from the Q+X-·ArOH complex was also discussed.View full abstractDownload PDF (913K) -
Dhananjaya NAUDURI, Gopu Bala Show REDDY1998 Volume 46 Issue 8 Pages 1254-1260
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of 3-styryl-1, 5-diphenyl and 5-styryl-1, 3-diphenyl 2-pyrazolines of different substitutions has been synthesized by condensation of substituted α, β-unsaturated ketones with phenylhydrazine hydrochloride in presence of catalytic amount of concentrated HCl. Compounds in the 3-styryl series had OMe, NMe2, NO2, OH and isopropyl substituents and those in the 5-styryl series had OMe, NMe2 and NOs. The 3-styryl-1, 5-diphenyl compounds showed little variation in antibacterial activity towards gram-positive and gram-negative bacteria in terms of geometric mean minimum inhibitory concentrations (MIC). The 4', 4''-NMe2, 4', 4''-NO2 and 4', 4''-OMe compounds were found to possess the highest activity in the series. The 5-styryl-1, 3-diphenyl series showed lower activities than the 3-styryl series. The in vitro antimycotic activity of the 4', 4''-OH and 2', 2''-OH substituted compounds showed good activity than the other molecules in the two series.View full abstractDownload PDF (884K) -
Jun YANAGIDA, Rinako MATSUHASHI, Ie WATANABE, Tadaaki SATOU, Kazuo KOI ...1998 Volume 46 Issue 8 Pages 1261-1264
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new subculture method and a novel microplate assay for nematocidal activity using a species of Diplogastridae have been developed. The assay gives results rapidly, with high sensitivity in 4h, and indicated good correlation between action mechanism and the nematode shape when examining 15 known compounds, including the antiparasitic avermectin, antimalarial quinine, and the γ-amino-n-butyric acidA (GABAA) activated Cl- channel antagonist picrotoxinin. Thus new assay could be used as a primary screening method for new nematocidal compounds.View full abstractDownload PDF (909K) -
Tomoo SUZUKI, Toshinao USUI, Mitsuru OKA, Tsunemasa SUZUKI, Tadashi KA ...1998 Volume 46 Issue 8 Pages 1265-1273
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn order to discover a medicine effective against Alzheimer's disease, we synthesized a series of quinoline derivatives having a characteristic 1-azabicyclo[3.3.0]octane amine ring, and performed pharmacological evaluation of them. Acetylcholine esterase inhibitory activities of these derivatives were unexpectedly weak. Tests for central nervous muscarinic cholinergic receptor binding affinity indicated that these compounds had higher affinities to muscarinic M1 receptors than to M2 receptors.A series of naphthalene derivatives substituted with the 1-azabicyclo[3.3.0]octane ring were also synthesized and muscarinic M1 and M2 receptor binding affinity deterimned. These compounds had much higher affinity for M1 receptors than the quinoline derivatives, and 1-[N-(1-azabicyclo[3.3.0]octan-5-yl)methyl-N-methylamino]-4-nitronaphthalene showed the highest affinity and selectivity. The ability of this compound to improve cognitive function was assessed using the passive avoidance test in scopolamine-induced mice.View full abstractDownload PDF (1371K) -
Ryo NAITO, Makoto TAKEUCHI, Koichiro MORIHIRA, Masahiko HAYAKAWA, Ken ...1998 Volume 46 Issue 8 Pages 1274-1285
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of 1-substituetd-4-piperidyl benzhydrylcarbamate derivatives were synthesized and evaluated for binding affinity to M1, M2 and M3 receptors, and for antimuscarinic activities. Receptor binding assays indicated that 1-benzyl-4-piperidyl benzhydrylcarbamate derivatives showed higher affinities for M1 and M3 receptors, and good selectivities for M3 over M2 receptor, than the corresponding ester analog. These results indicate that the urethane bond is a novel linker for muscarinic antagonists, and serves to lock the molecular conformation and allows the hydrophobic portion and cationic site of the molecule to bind to M1 and M3 muscarinic receptors. Among the prepared compounds, 1-(4-methylaminobenzyl)-4-piperidyl benzhydrylcarbamate monohydrochloride (18b, YM-58790) exhibited potent inhibitory activity on bladder pressure in reflexly-evoked rhythmic contraction, comparable to oxybutynin and was approximately ten times less inhibitory on oxotremorine-induced salivary secretion than oxybutynin in rats. Further evaluation of antimuscarinic effects on bradycardia and pressor in pithed rats, and on tremor in mice, demonstrate that YM-58790 can be useful for treatment of urinary urge incontinence as a bladder-selective M3 antagonist with fewer side effects.View full abstractDownload PDF (1461K) -
Ryo NAITO, Makoto TAKEUCHI, Koichiro MORIHIRA, Masahiko HAYAKAWA, Ken ...1998 Volume 46 Issue 8 Pages 1286-1294
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA novel series of biphenylylcarbamate derivaties were synthesized and evaluated for binding to M1, M2 and M3 receptors and for antimuscarinic activities. Receptor binding assays indicated that biphenyl-2-ylcarbamate derivatives had high affinities for M1 and M3 receptors and good selectivities for M3 receptor over M2 receptor, indicating that the biphenyl-2-yl group is a novel hydrophobic replacement for the benzhydryl group in the muscarinic antagonist field. In this series, quinuclidin-4-yl biphenyl-2-ylcarbamate monohydrochloride (81, YM-46303) exhibited the highest affinities for M1 and M3 receptors, and selectivity for M3 over M2 receptor. Compared to oxybutynin, YM-46303 showed approximately ten times higher inhibitory activity on bladder pressure in reflexly-evoked rhythimic contration, and about 5-fold greater selectivity for urinary bladder contraction against salivary secretion in rats. Moreover, selective antagonistic activity was also observed in vitro. Further evaluation of antimuscarinic effects on bradycardia and pressor in pithed rats, and on tremor in mice, showed that YM-46303 can be useful for the treatment of urinary urge incontinence as a bladder-selective M3 antagonist with potent activities and fewer side effects.View full abstractDownload PDF (1124K) -
Koichi MACHIDA, Rie ONODERA, Kyoko FURUTA, Masao KIKUCHI1998 Volume 46 Issue 8 Pages 1295-1300
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSNine new monoterpenoids, gardenamide (1), 6α-butoxygeniposide (2), 6β-butoxygeniposide (3), 6''-O-p-cis-coumaroylgenipin gentiobioside (4), and jasminosides A (6), B (7), C (8), D (9), E (10), were isolated from Gardeniae Fructus. Their structures were established on the basis of spectral analysis.View full abstractDownload PDF (860K) -
Tian-Shung WU, Yann-Lii LEU, Yu-Yi CHAN1998 Volume 46 Issue 8 Pages 1301-1302
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSeven denitroaristolochic acids, incuding four new compounds, sodium aristofolin-A, aristofolin-B-D and three known compounds, aristofolin-A, aristolic acid and methyl aristolate were isolated from the leaves of Aristolochia cucurbitifolia. Their structures were determined by spectroscopic methods.View full abstractDownload PDF (436K) -
Takashi ISHIZU, Shunsaku NOGUCHI1998 Volume 46 Issue 8 Pages 1303-1307
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSCyclo(Phe-Pro)4 (1) formed a 1 : 1 complex with noradrenaline hydrochloride (NAd·HCl) through intermolecular hydrogen bonds and a hydrophobic effects. The formation constant of the 1 : 1 complex of 1 with l-Nad·HCl was approximately 12.3 times that of the complex with d-Nad·HCl. It was presumed that the secondary hydroxy group of l-NAd·HCl formed an intermolecular hydrogen bond with Pro1 CO of 1, whereas that of d-NAd·HCl did not. The 1 : 1 complexes of 1 with various amine hydrochlorides were prepared.View full abstractDownload PDF (609K) -
Tokujiro KITAGAWA, Chinatsu TSUTSUI1998 Volume 46 Issue 8 Pages 1308-1310
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSN'-Chlorophenyl- and N'-chlorobenzyl-N-furfuryloxamides (6b-e and 7b-d) were synthesized through the reaction of chloro-substituted anilines (12b-e) or chloro-substituted benzylamines (13b-d) with N-furfuryloxamic acid sodium salt (10), which was prepared via condensation of methyl oxalate (8) with furfurylamine, followed by hydrolysis of the resulting amide-ester with sodium hydroxide. The activity of the prepared compounds (6 and 7) as plant growth regulators was examined by a germination assay using rape and leek seeds.N'-(3-Chlorophenyl)-N-furfuryloxamide (6c) showed a little effectiveness as an inhibitor, whereas the parent compound, N'-phenyl-N-furfuryloxamide (6a) inhibited the root growth of rape seedlings. The 2-chlorophenyl derivative (6b) inhibited the root growth of rape seedlings as potently as 6a, but sufficiently promoted the root growth of leek seedlings. Further, the 4-chlorophenyl derivative (6d) promoted the root growth of both species. On the other hand, in the series of chlorinated benzyl derivatives (7b-d), N'-(3-chlorobenzyl)-N-furfuryloxamide (7c) showed a markedly superior inhibitory effect in both species, but 2- and 4-chlorobenzyl derivatives (7b and 7d) inhibited the root growth of only rape seedlings.View full abstractDownload PDF (583K) -
Hitoshi ABE, Akira YAMASAKI, Takashi HARAYAMA1998 Volume 46 Issue 8 Pages 1311-1313
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new reagent system, phenyl trimethylsilyl selenide-aluminum bromide, was developed for the direct conversion of various benzylic hydroxy groups into a selenenyl group. Treatment of cinnamyl alcohol with this reagent system yielded 3, 4-dihydro-4-phenyl-2H-1-benzoselenin via a [3, 3]-sigmatropic rearrangement of the intermediate cinnamyl phenyl selenide.View full abstractDownload PDF (572K) -
Hikokazu SUZUKI, Magoichi SAKO, Kosaku HIROTA1998 Volume 46 Issue 8 Pages 1314-1316
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThermolysis of taxinine and taxinine H, esters of 2α, 9α, 10β-triacetoxy-8β, 12, 15α, 15β-tetramethyl-4-methylene-13-oxotricyclo[9.3.1.03, 8] pentadec-11-en-5α-ol, resulted in the smooth formation of the corresponding 4-en-4-ylmethanol esters and the 4(20), 5-diene by virtue of migration and elimination of the 5-O-ester moiety, thus providing useful methods for chemical modifications of the C-ring in taxinine derivatives.View full abstractDownload PDF (572K) -
Takeshi YAMAMOTO, Manabu HORI, Ikuo WATANABE, Hisayoshi TSUTSUI, Shoji ...1998 Volume 46 Issue 8 Pages 1317-1320
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSN-Isopropylation of methyl 2, 2-dimethyl-3-oxo-3, 4-dihydro-2H-benzo[1, 4]oxazine-6-carboxylate (2a) with various reagents was examined in order to prepare 3a, the key intermediate in the synthesis of N-(4-isopropyl-2, 2-dimethyl-3-oxo-3, 4-dihydro-2H-benzo[1, 4]oxazine-6-carbonyl)guanidine methanesulfonate (1, KB-R9032), a novel, potent Na/H exchange inhibitor. When a base such as sodium hydride, potassium carbonate or potassium tert-butoxide was used, the undesired O-isopropyl derivative 4a was produced as the main product. Among the hydrogen bond assisted mild bases examined, potassium fluoride (KF)-alumina afforded the best N-/O-selectivity with a ratio of about four. The undersired O-isopropyl derivative 4a could be easily converted to the starting 2a under non-aqueous acidic conditions. Combination of the above two processes increased the N-/O-ratio (to about 42). Consequently, the N-isopropyl derivative 3a was isolated without column chromatography in more than 70% yield. This KF-alumina catalyzed repeated isopropylation was applicable to N-selective alkylation of other hindered cyclic amides to afford N-alkyl derivatives in high yields.View full abstractDownload PDF (576K) -
Hiroaki TAKAYANAGI, Yumiko OSA, Tomoko SATO, Hiroshi TSUMURAYA, Kazuyo ...1998 Volume 46 Issue 8 Pages 1321-1324
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSConformational analysis of methyl 2, 3, 4-tri-O-acetyl-6-deoxy-6-(R)-phenylsulfinyl-α-D-glucopyranoside (1), methyl 2, 3, 4-tri-O-acetyl-6-deoxy-6-(S)-phenylsulfinyl-α-D-glucopyranoside (2) and methyl 2, 3, 4-tri-O-acetyl-6-deoxy-6-phenylsulfonyl-α-D-glucopyranoside (3) in solution (CDCl3) and the crystalline state was carried out using 1H-NMR spectra and X-ray crystallographic data. The conformational preference of the C6-S bond in the above mentioned compounds was found to be GT (GT is short for gauche-trans), and as a 1 : 1 mixture of rotamers for the (S)-S-oxide (2) and sulfone (3) but not in the (R)-S-oxide (1) in the solid state.View full abstractDownload PDF (568K) -
Akira KAJI, Kengo KIMURA, Masanori TERANISHI, Noriki KIRIYAMA, Masaaki ...1998 Volume 46 Issue 8 Pages 1325-1329
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAsterriquinone (ARQ, 1a) is an antitumor metabolite of Aspergillus terreus IFO 6123. To gain insight into the structure-activity relationships of ARQ, a series of chemically modified derivatives (1-6), the ARQ analogues (b-e) and the 2, 5-dihydroxy-p-bezoquinone analogues (f-h), were prepared, and cytotoxic acitivity against mouse leukemia P388 cells investigated. Results indicated that : 1) at least one hydroxy group or acetoxy group in the p-benzoquinone moiety is important to exhibit cytotoxicity; 2) in the p-benzoquinone moiety, a single methoxy group and/or one aceotxy group substitution showed more potent cytotoxicity than when two hydroxy groups are substituted (1); 3) the indole ring is important for the cytotoxicity of ARQ analogues; 4) the 1, 1-dimethly-2-propenyl group in the indole ring is not important for the cytotoxic activity of ARQ.View full abstractDownload PDF (731K) -
Toshihiro ISHII, Kazuhiko TAKATORI, Katsumi IIDA, Teruhiko HIGUCHI, Ak ...1998 Volume 46 Issue 8 Pages 1330-1332
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSWe have conducted optimizaiton studies to develop a superior 13C-phenylalanine breath test for the diagnosis of liver disease. First, we examined the optimum 13C-labeling position in phenylalanine for use in a breath test based on infrared spectroscopic detection of 13CO2 in exhaled air. L-[1-13C]Phenylalanine gave the best result. Next, a suitable dosage to give a short peak time (the time expressed in minutes as which 13CO2 excretion is maximal) after administration was determined. The 13CO2/12CO2 ratio in exhaled air after administration of 100 mg/body of L-[1-13C]phenylalanine peaked sharply at 15 min. We also examined the effect of food on the hepatic metabolism of L-[1-13C]phenylalanine. We found that a fasting period of over 7 h before the test resulted in a higher 13CO2 peak excretion. The peak appeared sooner than that in the 13C-phenacetin breath test and, therefore, the 13C-phenylalanine breath test appears preferable for the rapid evaluation of hepatic function.View full abstractDownload PDF (567K) -
Sandor KEKI, Tamas SIPOS, Gyorgy DEAK, Geza MEZEY, Miklos ZSUGA1998 Volume 46 Issue 8 Pages 1333-1334
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSMicroprecipitation of folic acid was monitored by the dynamic light scattering (DLS) method. The pH was changed by CO2 absorption and addition of HCl. The folic acid solutions were examined over the pH range 8.5-4.0. Over the pH range 5.4-6.0, microprecipitation was observed and at pH ≤5.2 crude precipitation of folic acid occurred. The dependence of the effective diameter on the pH over the pH range 5.4-6.0 is also reported.View full abstractDownload PDF (438K) -
Tomohiro MATSUSHIMA, Michiko MORI, Noriyuki NAKAJIMA, Hiroshi MAEDA, J ...1998 Volume 46 Issue 8 Pages 1335-1336
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe C1-C7 fragment (4) of tedanolide (1) was synthesized starting from methyl (R)-3-hydroxy-2-methyl-propionate via a mismatched but highly efficient Sharpless dihydroxylation of the C1-C7 α, β-unsaturated ester (6) with AD-mix-α.View full abstractDownload PDF (418K) -
Kentaro HATANO1998 Volume 46 Issue 8 Pages 1337-1338
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSRadiofluorination of protected methionine derivatives were examined in the presence of xenon difluoride (XeF2). The simple reaction procedure with 18F-tetrabutylammonium fluoride and XeF2 led N-Boc-methionine esters to corresponding 18F-fluoromethyl thioethers. The deprotection of the obtained labeled compounds was unsuccessful. This method expands the range of target molecules that can be labeled by fluorine-18 for noninvasive clinical measurements using positron emission tomography.View full abstractDownload PDF (388K) -
Masayuki YOSHIKAWA, Toshiyuki MURAKAMI, Kenichi YASHIRO, Hisashi MATSU ...1998 Volume 46 Issue 8 Pages 1339-1340
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA potent natural α-glucosidase inhibitor called kotalanol has been isolated from an antidiabetic traditional Ayurvedic medicine, the roots and stems of Salacia reticulata WIGHT, through bioassay-guided separation. The structure of kotalanol was elucidated on the basis of chemical and physicochemical evidence to be the inner salt comprised of 1-deoxyheptosyl-3-sulfate anion and 1-deoxy-4-thio-D-arabinofuranosyl sulfonium cation. Kotalanol was found to show more potent inhibitory activity against sucrase than salacinol and acarbose.View full abstractDownload PDF (422K) -
Hiroshi IMAGAWA, Tokuko SHIGARAKI, Tokiko SUZUKI, Hiroko TAKAO, Hideto ...1998 Volume 46 Issue 8 Pages 1341-1342
Published: August 15, 1998
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFive- and six-membered ring cyclic ethers are efficiently prepared by exo-mode oxymercuration of the corresponding olefinic alcohols with Hg(OTf)2. A seven-membered ring ether is prepared using Hg(OTf)2 along with TMU. However, this procedure is not effective for the preparation of four- and eight-membered ring ethers.View full abstractDownload PDF (385K)
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