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Volume 48, Issue 4
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Masayuki HATA, Yasuyuki FUJII, Miho ISHII, Tyuji HOSHINO, Minoru TSUDA2000 Volume 48 Issue 4 Pages 447-453
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe tetrahedral intermediate formation process, which is the first step in the deacylation reaction by class A β-lactamase, was investigated by the ab initio molecular orbital method. In this study, benzyl penicillin was used as the substrate. From the results of our molecular dynamics study of the structure of β-lactam antibiotics-β-lactamase complex, the substrate, Ser70, Lys73, Ser130, Glu166 and a water molecule for the deacylation reaction were considered for construction of a model for calculation. The calculation results indicated that Glu166 plays a role in holding a water molecule, which is necessary for the deacylation reaction, and that the hydrogen bond network among Lys73Nζ, Ser130Oγ, and the carboxy group of the β-lactam antibiotics was formed by the up-take of β-lactam antibiotics by β-lactamase. The activation energy for this reaction was 33.3 kcal/mol, and it is very likely that the reaction occurred at body temperature. Subsequent calculation results obtained by using the model excluding Ser130 and the carboxyl group of the substrate indicated that the activation energy for this reaction was 40.8 kcal/mol, which is 7.5 kcal/mol higher than that of the previous reaction. It was found that the hydrogen bond network plays an imortant role in decreasing the activation energy for the tetrahedral intermediate formation reaction. Lys73Nζ, which is located at the edge of the hydrogen bond network, played a role in forming a hydrogen bond with Glu166Oε in order to help the deacylation reaction. The role of amino acid residues around the active site of class A β-lactamase was also discussed.View full abstractDownload PDF (1072K) -
Takeo KAWAGUCHI, Tomohisa ICHIKAWA, Tetsuya HASEGAWA, Mineo SANEYOSHI, ...2000 Volume 48 Issue 4 Pages 454-457
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSixteen derivatives of 1-(β-D-arabinofuranosyl)-2-thiocytosine (araSC), including five 5'-esters, three 3'-es-ters, five N4-amides and three 5'-phosphodiesters, were synthesized and their reactivity to mouse tissue homogenates, including plasma, liver and intestine, and antitumor activity in mice bearing P388 cells were measured. The ester derivatives had a potent effect on the enzyme systems while the amide and phosphodiester derivatives were less active. The reactivity of ester derivatives was highly dependent on their chemical structure.The reactivity of amides and phosphodiester derivatives on mouse plasma and intestinal homogenate was also dependent on the chemical structure, although their action on intestinal enzymes was similar. Two of eight ester derivatives showed considerable antitumor activity in vivo, although they also showed serious toxicity indicated by a weitht loss in the mice. Four out of five amides and two out of three phosphodiesters showed antitumor activity, and two were highly effective (<200% in T/C, the ratio of the mean survival time of the treated group to that of the control group) with only a very slight weight loss.View full abstractDownload PDF (741K) -
Marta CASALDERREY, Consuelo SOUTO, Angel NONCHEIRO, Jose L. COMEZ-AMOZ ...2000 Volume 48 Issue 4 Pages 458-463
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree processed lactose-cellulose blends of similar composition, particle size and true density were compared as direct compression excipients : one was prepared by dry granulation, one by extrusion-spheronization, and the commercial product Cellactose. Differences among their flow properties depended solely on their different sphericities. Unlike those of the other blends, Cellactose particles exhibited numerous macropores. The mean yield pressures of all three blends were similar to those of direct compression lactoses. Cellactose tablets prepared at a punch pressure that largely eliminated macropores (pores <1μm) had better mechanical properties but much poorer disintegragtion than tablets of the other blends prepared at the same punch pressure. However, the tensile strength and disintegration time of Cellactose tablets both fell rapidly as macropore volume was increased by reducing punch pressure, while the enthalpy of wetting/dissolution rose. The strength and water-resistance of well-compacted Cellactose tablets is attributed to the spatial distribution of lactose and cellulose in Cel-lactose particles, rather than to β-lactose content or extra-particular structural features.View full abstractDownload PDF (1096K) -
Chikako HONDA, Hiroko KAMIZONO, Tomomi SAMEJIMA, Kazutoyo ENDO2000 Volume 48 Issue 4 Pages 464-466
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe irreversible thermal aggregation rate and process of bovine serum albumin (BSA) were investigated by means of light scattering technique as a function of temperature. The increasing rate of particle radius was affected by the aggregation temperature, concentration and the presence of fatty acid. The particle radius was larger and the aggregation rate was faster for fatty acid free BSA at higher temperature and concentration. Two thermal aggregation processes were observed at relatively low temperature and concentration, both for fatty acid containing (C-BSA) and fatty acid free BSA (F-BAS). The first process proceeds by an inter-monomer aggregation mechanism, and the second process by inter-aggregates aggregation. The first process is represented by a power law as Rhapp∝tz, which is diffusion limited cluster aggregation (DLCA).View full abstractDownload PDF (606K) -
Toshio AKIMOTO2000 Volume 48 Issue 4 Pages 467-476
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSN, N"-Propylenedinicotinamide (Nicaraven) is presently being developed for the tretment of cerebral stroke including subarachnoid hemorrhage. This drug is promising because some data suggest it to have an ability to scavenge the hydroxyl radical under physiological conditions in vivo, while it also has a high permeability through the blood brain barrier.Using the kinetic constant of the reaction between the hydroxyl radical and dimethyl sulfoxide, the formula derived by Babbs and Griffin (Free Rad. Biol. Med., 6 1989) was applied to obtain the kinetic constant of Nicaraven with the hydroxyl radical using a dimethyl sulfoxide-xanthine oxidase-hypoxanthine-Fe system, and this yielded the kinetic constant 3.4×109 M-1S<-1> (1M=1mol dm<-3>) for Nicaraven. Structurally related compounds were also investigated. The amide group of Nicaraven was thus found to play an important part in the reaction with the hydroxyl radical.Methanesulfinic acid, which was obtained from the reaction between dimethyl sulfoxide and the hydroxyl radical. was found to be stable under this adopted experimental condition and therefore was used to quantify the kinetic constant of Nicaraven.The structure of Nicaraven has also been investigated in CDCl3 using IR spectra, computer calculations and 1H-NMR analysis, and Nicaraven was thus shown to have an intramolecular hydrogen bond which froms a 7-membered ring that resembles a part of the 1H-1, 4-benzodiazepines. This structure may play an important role in the penetration through the blood brain barrier.View full abstractDownload PDF (1190K) -
Yuji MIKATA, Yoko ONCHI, Maki KISHIGAMI, Shigenobu YANO2000 Volume 48 Issue 4 Pages 477-479
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo bisquinoline derivatives, N, N'-bis(2-quinolylmethyl)ethylenediamine (2-BQME) and N, N'-bis(8-quinolylmethyl)ethylenediamine (8-BQME) have been synthesized, and their ability to bind to duplex DNA was studied. 8-BQME bound to DNA more strongly than 2-BQME, judging from the extent of increase in the melting temperature of duplex DNA, the UV-vis spectral change, and ethidium displacement assay. These compounds exhibited apparent AT-specificity suggesting minor groove binding in addition to intercalation.View full abstractDownload PDF (507K) -
Atsushi YAMAMOTO, Koji TOMOO, Hiroo MIYAGAWA, Yuji TAKAOKA, Shigeyuki ...2000 Volume 48 Issue 4 Pages 480-485
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTo promote our better understanding of the dynamic stability of the bovine cathepsin B structure, which is characterized by an extra disulfide bond at Cys148-Cys252 from the other species, and of the binding stability of CA074 (a cathepsin B-specific inhibitor), molecular dynamics (MD) simulations were performed for the enzyme and its CA074 complex, assuming a system in aqueous solution at 300k. The MD simulation covering 400 ps indicated that the existence of a Cys148-Cys252 disulfide bond increases the conformational flexbility of the occluding loop, although the conformational stability of the overall structure is little affected. The structural characteristics of the complex elucidated by X-ray analysis were suggested to be also intrinsic and stable in the dynamic state; the hydrogen bonding/electrostatic interactions between the main and side chains of CA074 and the Sn and Sn' subsites of the enzyme were maintained throughout the MD simulation. Furthermore, the simulation made clear that the binding of CA074 singificantly restricted the conformational flexibility of the substrate binding region, especially the occluding loop, of cathepsin B. Statistical analyses during the simulation suggest that the selectivity of CA074 for cathepsin B stems from the tight P1'-S1' and P2'-S2' interactions, assisted in particular by double hydrogen bonds between the carboxyl two oxygens of the CA074 C-terminus and the imidazole NH groups of His110 and His111 residues.View full abstractDownload PDF (927K) -
Akira IIDA, Masahiro KANO, Yoshihiro KUBOTA, Kenji KOGA, Kiyoshi TOMIO ...2000 Volume 48 Issue 4 Pages 486-489
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe pendant E-ring moiety of the podophyllotoxin aza-analogue 1 that is a potent inhibitor of microtubule assembly was modified in order to acquire inhibitory activity of DNA topoisomerase II. The monophenolic analogue 2 did not exhibit human topoisomerase II inhibition, while the ortho-quinone 3 that was obtained by oxidation of 2 inhibited its catalytic activity (decatenation) in a dose-dependent manner and stimulated double strand DNA break in supercoiled circular plasmid DNA, resulting in the production of linear DNA. These results showed that the topoisomerase II inhibition of the ortho-quinone 3 is due to stabilization of the topoisomerase II-DNA covalent binary complex. On the other hand, the ortho-quinone 3 did not inhibit the relaxation process of supercoiled DNA by topoisomerase I at concentrations up to 400 μM, nor was intercalation observed in unwinding measurements of 3. Therefore, the ortho-quinone 3 was shown to be a novel nonintercalative topoisomerase II specific inhibitor that stabilizes the cleavable complex. The present results suggest that the 4'-free hydroxyl group on the E-ring and the sugar moiety on the C-ring are not a prerequisite for topoisomerase II inhibition by podophyllotoxin derivatives.View full abstractDownload PDF (656K) -
Haruhiko HORINO, Tetsuya MIMURA, Syozo KOBAYASHI, Masahiro OHTA, Hideo ...2000 Volume 48 Issue 4 Pages 490-495
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS(-)-(3S, 4R, 1'R, 6'S)-4-(4-Benzyl-5-oxo-3, 4-diazabicyclo[4.1.0]hept-2-en-2-yloxy)-3, 4-dihydro-3-hydroxy-2, 2-dimethyl-2H-1-benzopyran-6-carbonitrile and its derivatives with a modified benzyl group were synthesized with the objective of discovering novel ATP-sensitive potassium channel openers (PCOs) with a slow onset of action and a reduced tendency to induce tachycardia. Among the compounds synthesized, 4-(2-chlorobenzyl) derivative 5bB had potent hypotensive activity in spontaneously hypertensive rats (SHRs). In addition, compound 5bB showed the desired pharmacological profile with a slow onset and long duration of action and induction of only mild tachycardia. Compound 5bB was found to be quantitatively metabolized in rats to give active des-2-chlorobenzyl derivative 6B. These results suggest that the incorporation of an N-benzyl group is a useful method for the preparation of prodruge, the function of which is to delay the onset and prolong the duration of action of the active substance.View full abstractDownload PDF (848K) -
Arjun Hari BANSKOTA, Yasuhiro TEZUKA, Kim Qui TRAN, Ken TANAKA, Ikuo S ...2000 Volume 48 Issue 4 Pages 496-504
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom the MeOH extract of leaves of Combretum quadrangulare, fifteen new cycloartane-type triterpenes, mehyl quadrangularates A-D (1-4) and N-P (8, 6, 12), methyl 24-epiquadrangularate C (5), quadrangularic acid E (9), 23-deoxojessic acid (10), 1-O-acetyl-23-deoxojessic acid (11), quadragularols A (7) and B (13) and norquadrangularic acids B (14) and C (15) were isolated together with two known cycloartane-type triterpenes, methyl 23-deoxojessate (16) and 4β, 14α-dimethyl-5α-ergosta-9β, 19-cyclo-24(31)-en-3β-hydroxy-4α-carboxylic acid (17). Betulinic acid (18), β-sitosterol (19), kamatakenin (20), isokaempferide (21), 5, 7, 4'-trihydroxy-3, 3'-dimethoxyflavone (22) and 5, 4'-dihydroxy-3, 7, 3'-trimethoxyflavone (23) were also obtained from the same extract. The structures of the new compounds were elucidated on the basis of spectral analysis and chemical conversions. All the isolated compounds were tested for their cytotoxicity towards highly liver metastatic murine colon 26-L5 carcinoma cells, and the cycloartane-type triterpenes showed various degrees of cytotoxicity, whereas all the flaconoids possessed strong cytotoxicity with ED50 values equal to or less than 6μM.View full abstractDownload PDF (1298K) -
Satoshi NISHIMUTA, Motohiko TAKI, Sachiko TAKAiSHI, Yasuteru IIJIMA, T ...2000 Volume 48 Issue 4 Pages 505-508
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSActivity-guided fractionation of twigs of Pistacia chinensis resulted in the isolation and characterization of two novel ingredients as potent estrogen agonists. On the basis of spectral analysis and comparison with a related compound their structures were elucidated as 3, 3"-dimers of 4-aryldihydrocoumarins (3, 4-dihydro-4-(4'-hydroxyphenyl)-7-hydroxycoumarin) differing only in the stereochemical disposition of the linkage between the two 4-arylcoumarin moieties. These compounds are the first examples of bis-flavonoids which have been proven to possess estrogen-like activity.View full abstractDownload PDF (569K) -
Noriaki KUDO, akamitsu YONEDA, Kazuo SATO, Toyokuni HONMA, Soji SUGAI2000 Volume 48 Issue 4 Pages 509-515
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS4-Sulfenyl-2-carbamoyl-4-isoxazolin-3-ones (4) were designed on the basis of biological isosterism and prepared in four steps. Some of these compounds showed sufficient pre-emergent herbicidal activities against various kinds of weeds. Among the synthesized compounds, 2-(N-(4-chlorophenyl)-N-isopropylcarbamoyl)-4-ethyl-thio-5-methyl-4-isoxazolin-3-one (4cd) exhibited the most promising activity.View full abstractDownload PDF (941K) -
Tsutomu WARASHINA, Tadataka NORO2000 Volume 48 Issue 4 Pages 516-524
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwenty-nine new oxypregnane glycosides were obtained along with two known cardenolides, frugoside and gofruside, and three known 12-O-acylated pregnane glycosides from the roots of Asclepias incarnata L.(Asclepiadaceae). By detailed studies of the 1H-and 13C-NMR spectra, the structures were determined to be tri- to penta glycosides of isolineolon, 12-O-acetyllineolon, ikemagenin, 12-O-benzoylisolineolon, and two new 12-O-acylated pregnanes.View full abstractDownload PDF (1224K) -
Hisao MATSUZAKI, Isao TAKEUCHI, Yoshiki HAMADA2000 Volume 48 Issue 4 Pages 525-528
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe mechanism of the liberation reaction of the N-oxide group has been studied and compared with the methylation reaction using a semi-empirical molecular orbital PM3 method. By comparing the calculated values of Gibbs free energy of activation, we can determine whether a liberation reaction or methylation reaction occurs.View full abstractDownload PDF (584K) -
Kiyoshi SUGI, Nobushige ITAYA, Tadashi KATSURA, Masami IGI, Shigeya YA ...2000 Volume 48 Issue 4 Pages 529-536
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSParoxetine, a potent and selective inhibitor of 5-hydroxytryptamine (serotonin) uptake, was prepared through a piperidine derivative, which was reported to be one of the paroxetine metabolites in humans.Thus, the piperidine derivative was converted to its N-tert-butoxycarbonyl (N-Boc) derivative, which was then converted to N-Boc paroxetine. Paroxetine hydrochloride propan-2-ol (isopropyl alcohol (IPA)) solvate crystals were directly obtained from the N-Boc Paroxetine by adding hydrogen chloride to the N-Boc paroxetine IPA solution. The amount of IPA content in the crystals was reduced by drying with a continuous change of powder X-ray diffraction patterns. Other characterizations of the solvate crystals were also conducted.View full abstractDownload PDF (900K) -
Noriko OKUMURA, Masashi GOTO, Bunji UNO2000 Volume 48 Issue 4 Pages 537-541
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSStructural and spectral characteristics of the electrogenerated tetracyanoethylene dianion (TCNE2-) were experimentally and theoretically examined. Spectroelectrochemistry of TCNE gives the spectra of TCNE2- in CH3CN at 220 nm, and in CH2Cl2 at 300 nm. These spectral characteristics are well explained by CIS/6-31G(d)and semiempirical CNDO/S-CI calculations. The bands in CH3CN and in CH2Cl2 are assigned to the degenerate 1E←1A1 transition at the D2d structure and the 1B2u←1Ag transition at the D2h structure, respectively. The rotation barrier of the C=C bond in TCNE2- is estimated by Hartree-Fock (HF), second-order Moller-Plesset perturbation (MP2) and fourth-order MP (MP4) calculations with 6-31G(d), 6-31+G(d) and 6-311+G(d) basis sets as 42-51 kJ mol-1. The D2d structure is most stable, and the D2h structure represents the transition state of the internal rotation. The calculations reveal that the two-electron addition to the antibonding LUMO of TCNE causes an easy rotation around the C=C bond of TCNE2- characterized by the formal single bond. These results show that TCNE2- preferentially adopts D2d and D<2h> structures in solvents depending upon the solvent nature by virtue of the easy rotation around the C=C bond.View full abstractDownload PDF (819K) -
Hirokazu SUDO, Toshinori IDE, Hideaki OTSUKA, Eiji HIRATA, Anki TAKUSH ...2000 Volume 48 Issue 4 Pages 542-546
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSExtensive isolation work on the n-BuOH-soluble fraction obtained from the leaves of Premna subscandens, collected on Ishigaki island, Okinawa, afforded six compounds. Two were identified as megastigmane glucosides, 7-(3, 5-dihydroxy-1, 1, 5-trimethylcyclohexylidene)-9-methylprop-8-enyl 9-O-β-ionol 9-O-β-D-glucopyranoside and 3-hydroxy-5, 6-epoxy-β-D-glucopyranoside. The structures of the remaining four new compounds were elucidated to be a 2'-O-β-D-apiofuranosyl derivative of 3-hydroxy-5, 6-epoxy-β-ionol 9-O-β-D-glucopyranoside, named premnaionoside, benzyl alcohol β-D-(2'-O-β-D-xylopyranosyl)glucopyranoside, phenethyl alcohol β-D-(2'-O-β-D-glucopyranosyl)glucopyranoside, and 4, 4'-dimethoxy-β-truxinic acid catalpol diester by spectroscopic analyses.View full abstractDownload PDF (773K) -
Hideaki OTSUKA, Eiji HIRATA, Anki TAKUSHI, Takakazu SHINZATO, Yoshio T ...2000 Volume 48 Issue 4 Pages 547-551
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom the leaves of Glochidion zeylanicum, six new butenolide glucoside, named glochidionolactones A-F, were isolated along with a known related compound, phyllanthurinolactone. The structures of glochidionolactones A-D and F were elucidated mainly by spectroscopic analyses. The absolute stereochemistry of glochidionolactone E was established by X-ray crystallographic analysis.View full abstractDownload PDF (810K) -
Hitoshi TAKAMI, Hiromi NONAKA, Nobuyuki KISHIBAYASHI, Akio ISHII, Hiro ...2000 Volume 48 Issue 4 Pages 552-555
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of 4-phenoxybutyric acid derivatives attached to a tricyclic skelton were prepared and evaluated as 5α-reductase inhibitors. Structure activity relationships for these compounds in terms of rat epididymls (type 2)5α-reductase inhibitory activities reveal that 1) the substitution pattern at the 11-position of dibenz[b, e]oxepin influenced potency, 2) higher lipophilicity of the tricylic skeleton improved potency, whereas the existence of a basic nitrogen atom in this skeleton was detrimental to potency, and 3) isobutyl substitution at the 8 position of the azepine skelton was tolerated. Among the tricyclic compounds studied, 4-[3-[5-benzyl-8-(2-methyl)propyl-10, 11-dihydrodibenz[b, f]azepine-2-carboxamido]phenoxy]butyric adid (26) was the most potent inhibitor of rat type 2 5α-reductase at 0.1μM.View full abstractDownload PDF (747K) -
Hitoshi YOSHIMITSU, Makiko NISHIDA, Toshihiro NOHARA2000 Volume 48 Issue 4 Pages 556-558
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFour new cholestane glycosides, nemed abutilosides D (1), E (2), F (3) and G (4), were isolated from the fresh roots of Solanum abutiloides. By chemical and spectroscopic evidence, their structures were elucidated as 26-O-β-D-glucopyranosyl 3β, 16α, 26-trihydroxy-5α-cholestan-22-one 3-O-β-D-xylopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranoside and its desxylosyl compound (1 and 3, respectively), 26-O-β-D-glucopyranosyl 3β, 16α, 26-trihydroxycholest-5-en-22-one 3-O-β-D-xylopyranosyl-(1→2)-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranoside and its desxylosyl compound (2 and 4, respectively). These compounds were regarded as precursors of a dormantinone type compound on a hypothetical pathway of steroid biogenesis.View full abstractDownload PDF (576K) -
K. V. RAO, A. K. SADHUKHAN, M. VEERENDER, V. RAVIKUMAR, E. V. S. MOHAN ...2000 Volume 48 Issue 4 Pages 559-562
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn the process development of lovastatin using Aspergillus terreus DRCC 152 in solid state fermentation, we have isolated a new butyrolactone-IV (3) along with the previously reported butyrolactone-I (1) and butyrolactone-II (2) produced under submerged conditions. The structure of compound 3 has been characterized as 3-hydroxy-5-{2-(1-hydroxy-1-methylethyl)-2-(R)-2, 3-dihydro-benzo[b]furan-5 ylmethyl}-4-(4-hydroxyphenyl)-5-methoxycarbonyl-(5R)-2, 5-dihydro-(5R)-2, 5-dihydro-2-furanone on the basis of spectroscopic studies. The absolute stereochemistry has been determined by single crystal X-ray diffraction studies. The cytotoxic and antibacterial activities of these compounds were determined.View full abstractDownload PDF (558K) -
Akihiko MIYADERA, Koji SATOH, Akihiro IMURA2000 Volume 48 Issue 4 Pages 563-565
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo efficient and practical methods of synthesis of the C-10 substituent of DV-7751 (1), a novel quinolone carboxylic acid, were established. The first method utilizes an optical resolution of racemic 8-amino-6-benzyl-6-azapiro[3.4]octane (13), while the second employs an enantioselective microbial reduction of 6-benzyl-5, 8-dioxo-6-azaspiro[3.4]octane (8b). The enantiomeric excess of (S)-8-amino-6-benzyl-6-azaspiro[3.4]octane (11) with each method of synthesis is greater than 96%.View full abstractDownload PDF (584K) -
Kaoru UMEHARA, Misae MATSUMOTO, Mitsuhiro NAKAMURA, Toshio MIYASE, Mas ...2000 Volume 48 Issue 4 Pages 566-567
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn the course of serching for differentiation inducers against leukemic cells from plants, we have recognized the differentiation inducing activities of the methanolic extract of Hydragea Dulcis Folium. Activity guided separation of the extract was carried out using M1 cells, and seven isocoumarins were isolated as active substances.These isocoumarins showed the activities at the concentration of 100 μM and non-cytotoxic effects even at 300 μM.View full abstractDownload PDF (493K) -
Xing-Hua ZHU, Tsuyoshi IKEDA, Toshihiro NOHARA2000 Volume 48 Issue 4 Pages 568-570
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree new glycosides named anguiviosides A-C were isolated from the fruits of Solanum anguivi and characterized as follows : 3-O-β-chacotrioside (1), 3-O-[4-O-maloyl-α-L-rhamnopyranosyl(1→2)]-α-L-rhamnopyranosyl(1→4)-β-D-glucopyranoside (2) and 3-O-α-L-rhamnopyranosyl(1→2)-[β-D-xylopyranosyl(1→3)]-β-D-glucopyranoide (3), of (25R, 26R)-spirost-5-en-3β, 26-diol.View full abstractDownload PDF (512K) -
Kazumasa AOKI, Kenji KOGA2000 Volume 48 Issue 4 Pages 571-574
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSEnantioselective deprotonation of 4-tert-butylcyclohexanone was examined using 1-phenylethylamine- and 1-(1-naphtyl)ethylamite-derived chiral lithium amides having an alkyl or a fluoroalkyl substituent at the amide nitrogen. The lithium amides having a 2, 2, 2-trifluoroethyl group on the amide nitrogen are easily accessible in both enantiomeric forms, and were found to induce good enantioselectivity in the present reaction.View full abstractDownload PDF (780K) -
Motoyuki TAGASHIRA, Takanori KITAGAWA, Naoko NOZATO, Seiji ISONISHI, A ...2000 Volume 48 Issue 4 Pages 575-578
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn the search for compounds which repress MDR1 gene expression, two novel aryl C-glycosides were isolated from a broth of Streptomyces sp. They had the characteristic structure of a dideoxy-carbohydrate (oliose or olivose) linked directly to chromomycinone, an aglycone of aureolic acids. Further investigation revealed that they were artifacts yielded from an aureolic acid mithramycin. Acid and methanol were necessary to yield the C-glycosides. This reaction would contribute to the design of useful aryl C-glycosides.View full abstractDownload PDF (564K) -
Kyoko KOFUJI, Tomohiro ITO, Yoshifumi MURATA, Susumu KAWASHIMA2000 Volume 48 Issue 4 Pages 579-581
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSChitosan (CS) forms a gel in solutions with a pH above 12, and the gelation occurs at pH of about 9 in 10% amino acid solutions. In this paper, we investigated the enzymatic degradation and the drug release profile of this novel CS gel beads. The degradability of the CS gel beads was affected by the CS properties, e.g. the degree of deacetylation. The release of prednisolone (PS), as a model drug, from the CS gel beads was sustained significantly compared with the gel prepared with NaOH only. However, the release was not able to be sustained by the increment of NaOH concentration in the solution employed for the preparation of CS gel beads. We also investigated the control of drug release from CS gel beads by application of a complex formed between chondroitin sulfate (Cho) and CS. The release of PS from the CS gel heads treated with Cho was prolonged, and the release pattern was not affected by the treatment time. The time to 50% drug release was about 5 min with PS powder, about 200 min in CS gel beads with 10% glycine (Gly) (pH9.0), and about 330 min in the CS gel beads with 10% Gly (pH9.0) treated with Cho. Thus CS gel beads pappear promising as a vehicle for sustained drug delivery, and the degradation of CS gel beads may be controlled by the degree of deacetylation of CS.View full abstractDownload PDF (492K) -
Yuko TAKEMURA, Keiko NAKAMURA, Tomiko HIRUSAWA, Motoharu JU-ICHI, Chih ...2000 Volume 48 Issue 4 Pages 582-584
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFour new furanone-coumarins, clauslactones-N (4), -O (5), -P (6) and -Q (7) were isolated from the leaves and twigs of Clausena excavata BURM. f. (Rutaceae) collected in Indonesia and their structures were elucidated by spectroscopic analysis.View full abstractDownload PDF (527K) -
Hirofumi TAKEUCHI, Takehiko YASUJI, Hiromitsu YAMAMOTO, Yoshiaki KAWAS ...2000 Volume 48 Issue 4 Pages 585-588
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe purpose of this study was to investigate the temperature-induced crystallization and the compactivility of the composite particles containing amorphous lactose and various types of polymers. The composite particles were prepared by spray-drying an aqueous solution of lactose and various types of gel forming water-soluble polymers at various formulating ratios.The stabilizing effect of hydroxypropylcellulose (HPC) and polyvinyl pyrrolidone (PVP) on amorphous lactose in the composite particles was smaller than that of sodium alginate in comparing at the same formulating ratios. The defference in the stability of amorphous lactose in the composite particles was attributed to the difference in the glass transition temperature (Tg) of the composite particles caused by the polymers formulated. The tensile strength of compacted spray-dried composite particles containing the polymers was highter than commercial lactose for direct tabletting (DCL21). The tensile strength of the composite particles was increased with an increase in water content in the particles. The difference in compactibility of the composite particls containing the different amount of polymer and water could be explained by the difference in Tg of the particles.View full abstractDownload PDF (1160K) -
Masakatsu SUGAHARA, Yasunori MORITANI, Tooru KURODA, Kazuhiko KONDO, H ...2000 Volume 48 Issue 4 Pages 589-591
Published: April 01, 2000
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS6, 7-Diethoxy-1-[1-(2-methoxyethyl)-2-oxo-1, 2-dihydropyridin-4-yl]naphthalene-2, 3-dimethanol [T-440, (1)]is a potential anti-asthmatic agent based on selective phosphodiesterase 4 inhibition. It was necessary for the further evaluation of 1 to develop an efficient synthetic route for 1, especially the construction of the 1-(2-methoxyethyl)-2-pyridone moiety. We examined an N-selective alkylation of pyridone derivative (2) in basic media, 2-Methoxyethylation of 2 with 2-methoxyethyl iodide utilizing LiH as the base gave predominantly an N-alkyl pyridone derivative (3a) in 82% yield (N/O-alkylation=92/8), which is compatible with an ab initio calculation of transition-state structures for the methylation of 2-pyridone. Single crystallization of a crude mixture of 3a and 4a furnished pure 3a, which is a key synthetic intermediate of 1.View full abstractDownload PDF (563K)
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