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Volume 45, Issue 1
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Haruko TAKECHI, Minoru MACHIDA1997 Volume 45 Issue 1 Pages 1-7
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSUpon irradiation of mono-, di-, and trithiobarbiturates in the presence of alkenes, [2+2]cycloaddition occurred regioselectively to give thietanes and their desulfurized products. In the case of trithiobarbiturate, a noevl type of ring contraction product, dithiohydantoin, was also obtained.View full abstractDownload PDF (921K) -
Tsutomu NAKANISHI, Yuka INATOMI, Masatoshi NISHI, Hiroko MURATA, Akira ...1997 Volume 45 Issue 1 Pages 8-12
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom whole fern, Diplazium subsinuatum (WALL. ex HOOK. et GREV.) TAGAWA, two new hopane-triterpene glycosides named diplaziosides III and IV were isolated, together with three new hopane glycosides with acetylated sugars. The structures of diplaziosides III and IV were established as (22S)-24-O-α-L-arabionofuranosyl-(1→2)-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranosyl-20α-O-β-D-glucopyranosyl-30-hydroxyhopan-28-oic acid (1) and (22R)-24-O-α-L-arabinofuranoyl-(1→2)-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranosyl-30-carboxy-17-hydroxy-hopano-28, 22-lactone (2), respectively, on the basis of spectral evidence. Diplazioside III (1) is novel not only in its glycoside structure, but also in its triterpene structure and moreover, 1 provides the first instance of a naturally occurring bisdesmoside with a hopane aglycone. The structures (3a, 3b, and 4a) of the acetylated glycosides were also elucidated, and this is the first report of naturally occurring acetates of hopane glycosides.View full abstractDownload PDF (783K) -
Protection of ψ(CH2NH) Peptide Bond with 2, 4-Dimethoxybenzyl Group in Solid-Phase Peptide SynthesisYusuke SASAKI, Junko ABE1997 Volume 45 Issue 1 Pages 13-17
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe reductive alkylation of a resin-bound amine by the Boc-amino aldehyde/NaBH3CN method is accompanied with undesirable double alkylation at Xaaψ(CH2NH)Gly sequences. To prevent the double alkylation, the utility of the 2, 4-dimethoxybenzyl (Dmb) group for secondary amine protection was investigated. By using this group, Leu-enkephalin and dynorphin (1-8) analogs containing the ψ(CH2NH) peptide bond between residues Tyr1/Gly2 or Gly2/Gly3 were synthesized in high yields.View full abstractDownload PDF (712K) -
Tooru KIMURA, Toshio FUKUI, Shigeki TANAKA, Kenichi AKAJI, Yoshiaki KI ...1997 Volume 45 Issue 1 Pages 18-26
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA reductive acidolysis final deprotection strategy in solid phase peptide synthesis was developed using a new safety-catch type of semi-permanent protecting groups and new linkers which were derived from 4-methylsulfinylbenzyl protection. This new strategy was based on a two-dimensional protection scheme employing acid-labile temporary and acid-stable but reductive acidolysis-cleavable semi-permanent protecting groups. By using this strategy, we successfully synthesized four model peptides, of which two contained C-terminal amide.View full abstractDownload PDF (1470K) -
Takeshi KOIKE, Mituharu TANABE, Naoki TAKEUCHI, Seisho TOBINAGA1997 Volume 45 Issue 1 Pages 27-31
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe reactions of sec-aminodienylesters 2, which were prepared by the reactions of methyl 5-(N, N-dimethylamino)-2, 4-pentadienoate (tert-aminodienylester 1) with primary amines, with acetaldehyde afforded 2, 3-dihydro-6H-1, 3-oxazines 3, providing a new heterocyclic annelation reaction.View full abstractDownload PDF (784K) -
Osamu KITAGAWA, Masao FUJITA, Midori OKADA, Takeo TAGUCHI1997 Volume 45 Issue 1 Pages 32-35
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSBeckmann rearrangement of O-4-pentenyl oxime derivatives proceeds in good yield under mild conditions through the formation of a cationic tetrahydrofuranium intermediate in the halocyclization reaction with N-bromosuccinimide.View full abstractDownload PDF (621K) -
Tatsuo NAGASAKA, Tomoko IMAI1997 Volume 45 Issue 1 Pages 36-42
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe chiral pyrrolidine derivatives, 4-(hydroxymethyl)-3-azabicyclo[3.1.0]hexan-2-ones (10 and 11) and 5, 5-disubstituted 2-pyrrolidinones (20, 21 and 22), were synthesized starting from (S)-pyroglutamic acid and absolute configuration determination was made based on the 1H-NMR spectra of the bicyclic lactam intermediates.View full abstractDownload PDF (1036K) -
Satoru KANEKO, Noriyuki NAKAJIMA, Tadashi KATOH, Shiro TERASHIMA1997 Volume 45 Issue 1 Pages 43-47
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn approach to 2, 2, 2-trifluoroethylidene derivatives from ketones was explored by employing the Corey-Winter's reductive elimination of 4-trifluoromethyl-1, 3-dioxolane-2-thiones to 2, 2, 2-trifluoroethylidene derivatives as a key step. The 1, 3-dioxolane-2-thione derivatives were readily prepared from ketones in five steps by sequential formation of O-silylated cyanohydrins, reduction, addition of trifluoromethyltrimethylsilane, desilylation, and formation of the 1, 3-dioxolane-2-thione system.View full abstractDownload PDF (916K) -
Chihiro ITO, Shinya KATSUNO, Hideki OHTA, Mitsuo OMURA, Ichiro KAJIURA ...1997 Volume 45 Issue 1 Pages 48-52
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSConstituents of the roots, the stem bark, and the leaves of Clausena excavata BURM. f. (Rutaceae) grown in a greenhouse at Okitsu Branch, Fruit Tree Research Station, Shizuoka, were studied. New carbazole alkaloids named clauszoline-H (1), -I (2), and -J (4) from the roots, clauszoline-K (6) and -L (7) from the stem bark, and clauszoline-M (8) from the leaves were isolated, together with known carbazoles and coumarins, and their structures were elucidated by spectroscopic methods.View full abstractDownload PDF (720K) -
Shinya HARUSAWA, Hideki MORIYAMA, Yoshihiko MURAI, Tomonari IMAZU, Hir ...1997 Volume 45 Issue 1 Pages 53-61
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe reaction of 2, 3, 5-tri-O-benzyl-D-ribose with the lithium salt of an imidazole derivative gave an adduct 17RS. Treatment of 17RS with 1.5N HCl in refluxing tetrahydrofuran gave the β-4(5)-ribofuranosylimidazole 19 (35%) and the ribosylimidazole 18 (51%). The latter was converted into β-19 in 86% yield by the Mitsunobu cyclization. This synthetic method produced only the desired β-anomer. Protection of the imidazole nitrogen of 19 with an ethoxycarbonyl group followed by debenzylation gave 21, which was successively derived to the 5'-amino derivative 1 via the 5'-substituted phthalimide 23, followed by hydrazine degradation in excellent yield. Compound 1 was then converted into the 5'-cyanoguanidine 2 in 79% yield. The 5'-amino derivatives 3-9 lacking a methyl group were efficiently synthesized. Among them, the cyanoguanidine 5 and phenylthiourea 8 exhibited antiulcer activities with half the efficacy of cimetidine. The molecular conformation of 5 was determined by X-ray structure analysis.View full abstractDownload PDF (1293K) -
Kazuko YOSHIKAWA, Aki MIZUTANI, Yukiko KAN, Shigenobu ARIHARA1997 Volume 45 Issue 1 Pages 62-67
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom the fresh stem of Stephanotis lutchuensis var. japonica, ten new oleanane-type triterpenoid glycosides, named sitakisosides XI-XX (1-10), were isolated. Their structures were determined on the basis of spectroscopic data and chemical evidence. The results show that all have a 3-O-β-D-xylopyranosyl(1→6)-β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl moiety and the aglycones of sitakisosides XI-XV, XVI and XVII, XVIII and XIX, and XX are sitakisogenin, chichipegenin, marsglobiferin and longispinogenin, respectively. Sitakisosides XI-XIII, XVI and XVIII, having an acyl group, showed antisweet activity.View full abstractDownload PDF (918K) -
Toshihiro FUJIOKA, Akio SAKURAI, Kunihide MIHASHI, Yoshiki KASHIWADA, ...1997 Volume 45 Issue 1 Pages 68-74
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSNine new triterpene glucosides, named cumingianosides G-O (4-7, 9, 12-15), containing a 14, 18-cycloapotirucallane-type skeleton were isolated from a cytotoxic fraction of the leaves of Dysoxylum cumingianum. The structures of the new compounds were established on the basis of chemical and spectral examinations. Evaluation of the cytotoxic activity of cumingianosides G-O showed that cumingianoside M exhibited significant (<4 μM) cytotoxicity, especially against leukemia and melanoma cell lines.View full abstractDownload PDF (927K) -
Taisuke ITAYA, Tae KANAI, Mitsuo IWATA, Masachika AZUMA1997 Volume 45 Issue 1 Pages 75-80
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS1-Methyl-5-(methylamino)imidazole-4-carbonitrile (4a) afforded three minor ring-opened products (5a, 6a, 10a) besides its 2-oxo derivative 3a on treatment with ethyl chloroformate in aqueous sodium bicarbonate. The geometrical isomers of these trisubstituted propenenitriles (5a, 6a, 10a) can be separated from each other by means of TLC, but equilibrate rapidly in solution. Because these compounds were converted into 3a in aqueous sodium hydroxide, alkaline treatment of the reaction mixture of 4a afforded a higher yield of 3a; although 3a also rapidly changed into other compounds in 0.1 N aqueous sodium hydroxide at room temperature, it could be recovered from the solution in high yield.5-Alkylamino homologues 3b, c were also prepared in 64% and 46% yields, respectively, by similar treatment of the substrates 4b, c having the 5-alkylamino substituents. The same products 3b, c were obtainable from the positional isomers 4d, e in 83% and 51% yields, respectively. These outcomes are interpretable by supposing that the reactions proceed through common intermediates, equilibrated mixtures of (E)- and (Z)-[2-(alkylamino)-1-cyano-2-(methylamino)ethenyl]carbamic acid ethyl esters (7).View full abstractDownload PDF (959K) -
Masayuki YOSHIKAWA, Toshiyuki MURAKAMI, Hajime KOMATSU, Nobutoshi MURA ...1997 Volume 45 Issue 1 Pages 81-87
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSix new furostanol saponins called trigoneosides Ia, Ib, IIa, IIb, IIIa, and IIIb were isolated from a medicinal foodstuff, fenugreek seed, the seed of Trigonella foenum-graecum L. (Leguminosae) originating from India, together with two known saponins, glycoside D and trigofoenoside A. The structures of trigoneosides Ia, Ib, IIa, IIb, IIIa, and IIIb were determined on the basis of chemical and physicochemical evidence as 26-O-β-D-glucopyranosyl-(25S)-5α-furostane-2α, 3β, 22ξ, 26-tetraol 3-O-[β-D-xylopyranosyl (1→6)]-β-D-glucopyranoside, 26-O-β-D-glucopyranosyl-(25R)-5α-furostane-2α, 3β, 22ξ, 26-tetraol 3-O-[β-D-xylopyranosyl (1→6)]-β-D-glucopyranoside, 26-O-β-D-glucopyranosyl-(25S)-5β-furostane-3β, 22ξ, 26-triol 3-O-[β-D-xylopyranosyl (1→6)]-β-D-glucopyranoside, 26-O-β-D-glucopyranosyl-(25R)-5β-furostane-3β, 22ξ, 26-triol 3-O-[β-D-xylopyranosyl (1→6)]-β-D-glucopyranoside, 26-O-β-D-glucopyranosyl-(25S)-5α-furostane-3β, 22ξ, 26-triol 3-O-[α-L-rhamnopyranosyl(1→2)]-β-D-glucopyranoside, and 26-O-β-D-glucopyranosyl-(25R)-5α-furostane-3β, 22ξ, 26-triol 3-O-[α-L-rhamnopyranosyl (1→2)]-β-D-glucopyranoside, respectively.View full abstractDownload PDF (898K) -
Yoshio OKADA, Yu MU1997 Volume 45 Issue 1 Pages 88-92
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS2-Adamantyl ester was examined for the selective protection of the γ-carboxyl function of the Glu residue, with the aim of preventing side reactions during peptide synthesis and increasing the solubility in organic solvents of peptide intermediates containing the Glu residue. Z-Glu(O-2-Ada)-OBzl was synthesized from Z-Glu-OBzl and admantan-2-ol with the aid of dicyclohexylcarbodiimide (DCC) and 4-N, N-dimethylaminopyridine (DMAP) in AcOEt. The 2-adamantyl ester group was stable to TFA, 20% piperidine/DMF and 10% Et3N/DMF up to 24 h and was easily removed by MSA, 1 M TFMSA-thioanisole in TFA, and HF. Therefore, H-Glu-(O-2-Ada)-OH could be applied for peptide synthesis in both solution and solid phase methods in combination with a Boc or Fmoc group as the Nα-protecting group. Boc-Glu(O-2-Ada)-OH was successfully employed for the synthesis of Bz-Ile-Glu-Gly-Arg-CH2Cl, an irreversible inhibitor of factor Xa.View full abstractDownload PDF (778K) -
Tadashige CHIBA, Toshifumi AKIZAWA, Motomi MATSUKAWA, Nobufumi KAWAI, ...1997 Volume 45 Issue 1 Pages 93-100
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn order to study the structure-activity relationships of spidamine and joramine found in the venom of Joro spider, Nephila clavata, we attempted to synthesize various analogs. Six analogs were convergently synthesized according to our previous method for the synthesis of spidamine, N-(3-aminopropyl-β-alanyl)-N'-(2, 4-dihydroxy-phenylacetyl-L-asparaginyl)-1, 5-pentanediamine and joramine, N-(3-aminopropyl-β-alanyl)-N'-(4-hydroxyphenyl-acetyl-L-asparaginyl)-1, 5-pentanediamine. The biological activities of the analogs and four intermediates were compared with those of synthetic spidamine and joramine in three bioassay systems, lobster neuromuscular synapse, cockroaches and mosquito larvae. The glutamate receptors in these systems were inhibited by some analogs, and the D-asparagine- or indoleacetyl-containing analogs were found to be strong inhibitors. These compounds have potential application as insecticides.View full abstractDownload PDF (1243K) -
Takeshi SUZUKI, Akira MATSUHISA, Keiji MIYATA, Isao YANAGISAWA, Mitsua ...1997 Volume 45 Issue 1 Pages 101-106
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSNovel 9-methyl-4, 9-dihydrothiopyrano[2, 3-b]indol-4-one derivatives 2b-e, 3-methylene-9-methyl-2, 3, 4, 9-tetrahydrothiopyrano[2, 3-b]indol-4-one derivatives 3b-e and 9-methyl-2, 3, 4, 9-tetrahydrothiopyrano[2, 3-b]indol-4-one derivatives 4a-e were prepared. The 5-hydroxytryptamine (5-HT3) receptor-antagonistic activities of these compounds were evaluated by using the von Bezold-Jarisch reflex test (B. J. reflex, rats) and the contractile response to 5-HT in the isolated distal colon (guinea pig). The 5-ethyl-4-imidazolyl derivative 4d was found to be 79 times more potent than ondansetron 1 in the B. J. reflex test (ID50=0.048 μg/kg, i.v.), and the 5-methyl-4-imidazolyl derivative 4c was found to be 126 times more potent than 1 in the colonic contraction (IC50=0.0062 μM) assay.View full abstractDownload PDF (995K) -
Kenichi SATO, Junko NAKAGAWA1997 Volume 45 Issue 1 Pages 107-115
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn applying the neural network to the classification problem in pharmacology, we adopt an extended back-propagation (EBP) learning which adjusts the parameters appearing in an activation function, as well as the weights. The results of simulations show that such an extended learning speeds up the learning process as compared with the conventional basic back-propagation procedure, irrespective of the initial values of the parameters, which is extremely useful in the practical application of the neural network in the pharmaceutical field. We have also found that use of Morita's activation function beyond the sigmoid type further accelerates the EBP learning in some cases.View full abstractDownload PDF (1100K) -
Yasuyuki KAWANISHI, Shoichi ISHIHARA, Kimio TAKAHASHI, Tadahiko TSUSHI ...1997 Volume 45 Issue 1 Pages 116-124
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn an attempt to improve the low oral absorbability of previously reported dual histamine H2 and gastrin receptor antagonists, compounds of a different type were synthesized and evaluated for biological activity. These new compounds bear a histamine H2 receptor antagonist (H2A) pharmacophore moiety attached to a gastrin receptor antagonist (GA) pharmacophore moiety in a reversed manner, namely the head-to-head manner, different from the previously reported head-to-tail manner. These new hybrid compounds were classified into three types : type I, the regular amide type bearing a roxatidine moiety; type II, the reversed amide type bearing a roxatidine moiety; and type III, hybrid compounds bearing a famotidine moiety directly connected to a GA moiety without a spacer. Among them, only (R)-1-[3-(N'-{4-[2-(N-aminosulfonylamidino)ethylthiomethyl]thiazol-2-yl}guanidinomethyl)phenyl]-3-(1-methyl-2-oxo-5-phenyl-2, 3-dihydro-1H-1, 4-benzodiazepin-3-yl)urea (42), belonging to type III, showed a weak but distinct histamine H2 receptor-antagonistic activity as well as a modest gastrin receptor-antagonistic activity. Of most importance was the finding that this compound showed a weak but clearly improved in vivo oral antigastric acid secretory activity as a result of the structural changes, including the decreased molecular weight.View full abstractDownload PDF (1354K) -
Ryoichi UNNO, Hisashi MICHISHITA, Hideaki INAGAKI, Yutaka BABA, Takahi ...1997 Volume 45 Issue 1 Pages 125-133
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSNovel cyclic enediyne compounds, which are simple functional analogs of dynemicin A (1) having the bicyclo-[7.3.1]tridec-4-ene-2, 6-diyne system, were synthesized and evaluated for the DNA-cleaving ability, in vitro cytotoxicity and in vivo antitumor activity. All of the sulfones 19-24, which were equipped with a 2-(arylsulfonyl)-ethoxycarbonyl group or the 2-(methylsulfonyl)ethoxycarbonyl group as a triggering device, showed both potent DNA- cleaving activity and cytotoxicity against various tumor cell lines. However, these compounds were entirely inactive or only slightly active against murine P388 leukemia in mice. On the other hand, the enediyne 2a having a phenyl carbamate moiety as a stable N-protecting group showed effective antitumor activity both in vitro and in vivo. In particular, it exhibited significant antitumor activity against Lewis lung carcinoma in mice. These results show that the character of the carbamate moiety of the cyclic enediynes strikingly affects their biological activities, that is, the sulfonylethyl carbamate moiety is an effective triggering device for both DNA-cleaving activity and cytotoxicity, and the phenyl carbamate moiety is significant for antitumor activity in vivo. As part of a mechanistic study, the reactivities of 2a and 21 were examined under a weakly basic condition (pH 9.3); both compounds failed to give the Bergman cycloaromatization product.View full abstractDownload PDF (1420K) -
Naoyuki HARADA, Takayuki KAWAGUCHI, Isao INOUE, Motoaki OHASHI, Kouji ...1997 Volume 45 Issue 1 Pages 134-137
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSVarious kinds of water-soluble quaternary salts of 2-(2'-oxoalkoxy)-9-hydroxyellipticines were synthesized in a search for compounds with potent antitumor activity and low toxicity. Some compounds exhibited more potent antitumor activities than elliptinium (1) and SUN 4599 (3). In particular, 2-(3'-methoxy-2'-oxopropanoxy)-9-hydroxy-5, 11-dimethyl-6H-pyrido[4, 3-b]carbazolium bromide (4d) showed potent antitumor activities against P388 leukemia, colon 26, and Lewis lung carcinoma.View full abstractDownload PDF (590K) -
Satoshi SHUTO, Takumi OBARA, Satoshi YAGINUMA, Akira MATSUDA1997 Volume 45 Issue 1 Pages 138-142
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSWe previously synthesized (6'R)- and (6'S)-6'-C-methylneplanocin A's (2a and 2b, respectively), and found that one of them has a potent antiviral activity, though its 6'-configuration has not been confirmed. This report describes the determination of the 6'-configuration and practical preparation of the antivirally active diastereomer. The 6'-configuration of the active diastereomer was determined as R by the modified Mosher's method as well as by synthesizing 2b from the known cyclopentenone derivative 10. A practical method for preparing the 6'R-diastereomer was developed by using diastereoselective deamination with Ado deaminase as the key step. Treatment of the diastereomeric mixture of 2a and 2b, which was prepared via an addition reaction of Me3Al with the 6'-formyl derivative 3, with Ado deaminase from calf intestine, deaminated 2b selectively to give the corresponding (6'S)-inosine congener 5, and left the desired 2a not deaminated. After silica gel column chromatography, 2a was obtained in a pure form.View full abstractDownload PDF (708K) -
Hajime KATAYAMA, Naoyuki TAGAWA, Yusuke KAWADA, Keiichi SHIOBARA, Kimi ...1997 Volume 45 Issue 1 Pages 143-147
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of 3-oxo-3H-pyrazolo[1, 5-a]indole derivatives was prepared and characterized as heterocyclic analogues of quinone methide. These compounds showed some cytotoxicity to cancer cells, but were ineffective in an in vivo test against murine leukemia L1210.View full abstractDownload PDF (855K) -
Toshikazu SEKINE, Nobuaki FUKASAWA, Fumio IKEGAMI, Kazuki SAITO, Yuich ...1997 Volume 45 Issue 1 Pages 148-151
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new monoterpenoidal carboxamide, concinnamide (1), has been isolated from the seeds of a Thai medicinal plant, Acacia concinna DC. (Leguminosae). Its structure has been revised to (E)-2, 6-dimethyl-6-hydroxy-2, 7-octadienamide by detailed spectroscopic and synthetic studies, though it had been preliminarily assigned as a seven-membered lactam derivative by our previous work. (-)-Concinnamide, (-)-1, was synthesized from (-)-linalool (2) by stepwise oxidation, followed by amidation to confirm the structure. The inhibitory effects of 1 and related compounds on the arachidonate 5-lipoxygenase of RBL-1 cells are also described.View full abstractDownload PDF (643K) -
Haruhisa KIZU, Yoshitaka IMOTO, Tsuyoshi TOMIMORI, Tohru KIKUCHI, Shig ...1997 Volume 45 Issue 1 Pages 152-160
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFive neoclerodane-type diterpenoid lactones, scuterivulactones A, B, C1, C2 and D, have been isolated (scuterivulactone C2 was separated as the acetate) from the whole herb of Scutellaria rivularis WALL. (Labiaceae), and their structures have been determined based on chemical and physicochemical evidence as follows : scuterivulactone A, (4S, 11S)-11-acetoxy-6α-benzoyloxy-3, 4-epoxy-8β-hydroxy-13(14)-neocleroden-15, 16-olide; scuterivulactone B, (4R, 13R)-11β-acetoxy-6α-benzoyloxy-8β, 13-epoxy-3-oxo-15, 16-neoclerodanolide; scuterivulactone C1, (4R, 13R)-11β-acetoxy-6α-benzoyloxy-3α, 4β-dihydroxy-8β, 13-epoxy-15, 16-neoclerodanolide; scuterivulactone C2, (4R*, 13S*)-11β-acetoxy-6α-benzoyloxy-3α, 4β-dihydroxy-8β, 13-epoxy-15, 16-neoclerodanolide; and scuterivulactone D, (4R)-6α-benzoyloxy-3α, 4β-dihydroxy-11, 13(14)-neoclerodadien-15, 16-olide.View full abstractDownload PDF (1133K) -
Hiroshi MORITA, Akira GONDA, Koichi TAKEYA, Hideji ITOKAWA, Osamu SHIR ...1997 Volume 45 Issue 1 Pages 161-164
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree-dimensional structures in dimethyl sulfoxide (DMSO)-d6 of three proline-rich cyclic nonapeptides, cycloleonuripeptides A : cyclo (-Gly-Pro-Pro-Pro-Tyr-Pro-Pro-Met-Ile-), B : cyclo (-Gly-Pro-Pro-Pro-Tyr-Pro-Pro-Met(O)-Ile-), and C : cyclo (-Gly-Pro-Pro-Pro-Tyr-Pro-Pro-Met(O)-Ile-), which have been isolated from the fruits of Leonurus heterophyllus, were determined by distance geometry calculation and restrained energy minimization from NMR data. Calculation using 272 different initial structures led to a uniquely determined backbone conformation with a root mean square deviation value of 0.57 Å. The backbone structures of cycloleonuripeptides A, B, and C consist of two β-turns, a β VI turn at Pro3-Pro4, and a β I turn at Pro7-Met8. In addition to a transannular 4→1 backbone hydrogen bond between Tyr5-NH and Pro2-CO, two intramolecular hydrogen bonds between Gly1-NH and Pro6-CO, and between Ile9-NH and Pro6-CO, which constructed a β-bulge conformation, were observed.View full abstractDownload PDF (663K) -
Kazuhiko OZAKI, Masahiro HAYASHI1997 Volume 45 Issue 1 Pages 165-170
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSLiposomes were freeze-dried with glucose oligomers(maltodextrins) consisting of 2 (maltose) to 7 (maltoheptaose) glucoside units, and the effects of the glucoside unit number of the maltodextrin on the lyophilization of the liposomes were investigated. When the molar ratio of the glucoside units of maltodextrins to lipids was reduced below 6, two distinct endotherms were observed after annealing the freeze-dried L-α-dipalmitoylphosphatidylcholine (DPPC) liposome by differential scanning calorimetry (DSC). When the molar ratio was raised above 6, only the lower of the two endotherms was observed in all maltodextrins tested. At a molar ratio 6, the gel to liquid crystalline transition temperature (Tm) of the first scan of these samples was measured. The Tm with maltose was observed to be ca. 65°C, whereas the Tm with the other maltodextrins was observed to increase as the number of glucoside units was increased. Using Fourier transform IR, the phosphate asymmetric stretching band of DPPC liposomes lyophilized with these maltodextrins was observed to shift to lower frequencies. In all cases, the phosphate asymmetric stretching was observed to be roughly 1240 and 1224 cm-1 in the presence of these saccharides. The ratio of the absorbance at 1224 to that at 1240 cm-1 of DPPC liposomes freeze-dried with maltose was greater than the ratio of those stabilized with any of the other maltodextrins tested. These results suggest that the rate of hydrogen bonding between the phosphate of the lipid and maltodextrins was highest when maltose was used as the cryoprotectant. Because of this interaction, the space between the lipid molecules may become wider, causing an increase in the flexibility of the liposomal membrane.View full abstractDownload PDF (759K) -
Joao Fernandes PINTO, Fridrun PODCZECK, John Michael NEWTON1997 Volume 45 Issue 1 Pages 171-180
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe dissolution profile of a model drug (indomethacin) in pellets produced by extrusion and spheronisation has been evaluated according to the method described in the USP XXIII, apparatus II. The effects of the speed of the paddles, temperature, pH and size of the pellets, i.e., the surface area have been examined. The study was complemented by coating the pellets with a polymer (ethylcellulose) in an aqueous dispersion and changes in the release of the drug were monitored. The analysis of the results was carried out by determination of two statistical moments mean dissolution time (MDT) of indomethacin and variance of dissolution time (VR) and an associated parameter, the relative dispersion of the concentration-time profile (RD). From these parameters, it was possible to relate the release of the drug to the dissolution mechanisms and models described in the literature. The present study has shown the possibility of analysing the complete release of the indomethacin as opposed to the traditional approach of considering only 40-60% of the drug released. The analysis has also shown that the mechanism of release of the drug changes throughout the test. Finally, for pellets coated with ethylcellulose, the coating altered the rate of release of the drug and changes in the release mechanism were also observed. Under certain conditions a zero order release rate was obtained.View full abstractDownload PDF (1205K) -
Alejandro MARTINEZ, Carmenza DUQUE, Naoko SATO, Yoshinori FUJIMOTO1997 Volume 45 Issue 1 Pages 181-184
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSMethanolic extracts of the marine sponges Ircinia felix, I. strobilina and I. campana occurring in the Colombian Caribbean afforded similar complex mixtures of antimicrobial furanosesterterpene tetronic acids. Each mixture was acetylated and then fractionated by HPLC. GC, GC-MS and NMR analyses of the HPLC fractions revealed the novel (8Z, 13Z, 20Z)-strobilinin and (7Z, 13Z, 20Z)-felixinin, together with the known (8E, 13Z, 20Z)-strobilinin, (7E, 13Z, 20Z)-felixinin and (7E, 12E, 18R, 20Z)-variabilin.View full abstractDownload PDF (717K) -
Katsuhiro KONNO, Katsuji OJIMA, Takaaki HAYASHI, Miyuki TANABE, Hiroak ...1997 Volume 45 Issue 1 Pages 185-188
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSSynthesis of a 1α, 25-dihydroxyvitamin D2 analog (3), in which the double bond in the side-chain in replaced by an amide group, is described. Condensation of a carboxylic acid (8) with an amine (6) gave an amide (9), which in turn led to 3 via several steps. The analog (3) could not bind to the chick cytosol vitamin D receptor, which indicated the importance of the hydrophobic interaction of the C(22)-C(23) double bond in 1α, 25-dihydroxyvitamin D2 (2) with the vitamin D receptor.View full abstractDownload PDF (605K) -
Hideaki SASAKI, Atsumi SUEHIRO, Yasuyuki NAKAMOTO1997 Volume 45 Issue 1 Pages 189-193
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe novel heterocyclophanes, 3, 6, 21, 24-tetraaza[8.8](2, 2')(4, 4'-bithiazolophane) (3a) and 3, 7, 22, 26-tetraaza-[9.9](2, 2')(4, 4'-bithiazolophane) (3b) were readily synthesized by the cyclization of 1, 4-dibromobutane-2, 3-dione with N, N'-bis(tert-butoxycarbonyl)ethylenediamine-N, N'-dipropionthioamide and N, N'-bis(tert-butoxycarbonyl)-trimethylenediamine-N, N'-dipropionthioamide, respectively, followed by acidic deprotection. Under physiological conditions, 3a and 3b at 5 μM showed considerable DNA-cleaving activities in the presence of Co(II) without any reducing agent.View full abstractDownload PDF (945K) -
Kazuhiro OHKI, Naoki SAKURA, Tadashi HASHIMOTO1997 Volume 45 Issue 1 Pages 194-197
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe acid hydrolysis of thyrotropin releasing hormone (TRH) (pGlu-His-Pro-NH2) in various acids under several conditions and the highly selective cleavage of the pGlu-His bond are described. First, the decomposition of TRH in dilute acid was studied. The incubation of TRH in 1 N HCl at 60°C resulted in the formation of eleven hydrolysates, H-Glu-His-Pro-NH2, H-Glu-His-Pro-OH, H-His-Pro-NH2, H-His-Pro-OH, His-Pro diketopiperazine, pGlu-His-Pro-OH, pGlu-His-OH, H-Glu-His-OH, H-Pro-His-OH, pGlu-OH and H-Glu-OH. The results showed that the pGlu-His linkage and pGlu moiety were more sensitive than the C-terminal carboxamide to the acid hydrolysis. Then, a simple means of deblocking pGlu-peptide was applied to TRH. The hydrolysis of TRH in 70% methanesulfonic acid (MSA) at 25°C produced H-His-Pro-NH2 and H-His-Pro-OH as major products, and H-Glu-His-Pro-NH2, the diketopiperazine and pGlu-His-Pro-OH as minor products. The 90% MSA hydrolysis at 25°C was highly selective for the cleavage product (H-His-Pro-NH2) of the pGlu-His bond, without affording the ring-opened products (H-Glu-His-Pro-NH2 and H-Glu-His-Pro-OH). The yield of deamidated products (H-His-Pro-OH and pGlu-His-Pro-OH) was less than 3% after 3 d.View full abstractDownload PDF (655K) -
Shigeko OZAKI, Eiki MATSUI, Hidenobu OHMORI1997 Volume 45 Issue 1 Pages 198-201
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe addition of butyl radicals to β- and/or γ-disubstituted α-methylenebutyrolactones by a nickel(II) complex-catalyzed indirect electroreduction using equimolar amounts of butyl iodides and α-methylenebutyrolactones provides cis-(C-α) : (C-β)-trisubstituted lactones as the major product. The addition was successful because the present method to permits long lifetimes for the initial butyl radicals and decreases lifetimes of the final adduct radicals by selective reduction of these radicals.View full abstractDownload PDF (743K) -
Toshihiro FUJIOKA, Akio SAKURAI, Kunihide MIHASHI, Yoshiki KASHIWADA, ...1997 Volume 45 Issue 1 Pages 202-206
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSDetailed chemical studies on the cytotoxic fraction from the leaves of Dysoxylum cumingianum have resulted in the isolation of two new triterpene glucosides, cumingianosides P (18) and Q (19), with an apotirucallane-type skeleton. The structures of 18 and 19 were determined by spectral examinations, and by conversion of cumingianosides C (3) and A (1) into 18 and 19, respectively. The cytotoxicities of cumingianosides P and Q against over 50 human cancer cell lines were evaluated. Cumingianoside P exhibited significant (EC50 <4 μM) cytotoxicity against 37 human cancer cell lines. Among them, the UO-31 (renal cancer) cell line was the most sensitive to this compound (EC50 0.267 μM). In contrast, cumingianoside Q showed selective cytotoxicity against NCI-H522 (non-small cell lung cancer) cells with an EC50 value of 1.67 μM, and exhibited no cytotoxicity (EC50 >10 μM) against most of the remaining cancer cell lines.View full abstractDownload PDF (633K) -
Takamasa IIMORI, Isao AZUMAYA, Yasuo HAYASHI, Shiro IKEGAMI1997 Volume 45 Issue 1 Pages 207-208
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA practical and economical resolution of endo-bicyclo[3.3.0]oct-7-en-2-ol and endo-bicyclo[3.3.0]oct-6-en-2-ol was accomplished via lipase-catalyzed enantioselective irreversible transesterification with vinyl acetate.View full abstractDownload PDF (467K) -
Hidenori AZAMI, David BARRETT, Toshiyuki CHIBA, Akihiko FUJIKAWA, Kazu ...1997 Volume 45 Issue 1 Pages 209-213
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new, potent 1β-methylcarbapenem (FR21751) containing a novel pyridiniomethylpyrrolidine side chain has been synthesized, and was found to undergo epimerization at the pyrrolidine C-2 position. To investigate this isomerization, we evaluated the epimerization rate by HPLC at various pH values in aqueous solution and the deuterium exchange rate by 1H-NMR spectroscopy in buffered D2O solution. The rate of this epimerization was greater at high pH (≥6), and deuterium exchange occurred only at the benzylic position of the pyridine ring. The results can be interpreted in terms of a mechanism involving anionic and acyclic intermediates. We synthesized the postulated acyclic intermediate of this epimerization independently and demonstrated its cyclization to give a mixture of four diastereomers (6a, 9), in support of our proposed mechanism.View full abstractDownload PDF (687K) -
Guojie XU, Hisakazu SUNADA, Ruhua ZHANG1997 Volume 45 Issue 1 Pages 214-216
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSHydroxypropyl methylcellulose has been used as a rate-controlling polymer in indomethacin controlled release tablet formulations. Examination was made of the feasibility of manufacturing indomethacin-controlled matrix tablets using an agitating fluid bed and extrusion granulators. The results indicated that 1) the agitating fluid bed granulator gave porous granules; 2) geometric median diameter and granule hardness were directly correlated with the concentration of the binder solution (at the range of 0.75-1.50% of HPMC) sprayed on the powder bed when using the agitating fluid bed; 3) granule flowability for the two granulators was essentially the same; 4) extrusion granulation led to high granule hardness; 5) parameters determined using Kawakita's equation indicated granules made by the agitating fluid bed were compressible, while those by extrusion showed good filling; 6) tablet diametrical tensile strength was related to granule hardness and geometric median diameter. High granule hardness and small geometric median diameter resulted in high tablet diametrical tensile strength.View full abstractDownload PDF (569K) -
Kotaro IIDA, Koji AOKI, Kazumi DANJO, Akinobu OTSUKA, Cheng Yu CHEN, E ...1997 Volume 45 Issue 1 Pages 217-220
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe influence of basic properties such as physicochemical or particle properties on the mechanical properties of celluloses with different average degrees of polymerization ((DP)^^-), which included powdered α-cellulose and its degradation products as well as commercial microcrystalline celluloses, was investigated. The particle shape approached that of a sphere with a reduction in (DP)^^-, causing an increase in flowability and a decrease in the cohesion of cellulose powders. Hmax and γ in the Leuenberger equation, which were considered to reflect the compactibility and compressibility of powders, respectively, were higher at a lower (DP)^^-, suggesting that the particle shape and/or crystallinity of materials affected the bonding properties of a substance in tablet preparation. The mechanical strength was estimated using the crushing test for a granule and the diametral compression test for a tablet. Crushing work, W, increased with a decrease in (DP)^^-, which was probably due to a decrease in granule porosity. The compression behavior of granules was estimated by the static method, using the Heckel equation. The compression coefficient, K, in this equation decreased with the crushing work of a granule, thus the reciprocal of K was expected to be a measure of granule strength. The tensile strength of a tablet increased with the crushing work of a granule in the relatively high (DP)^^- region. When the (DP)^^- was low, the crushing work of granule was high and tablet strength tended to reach a maximum.View full abstractDownload PDF (618K) -
Hiraku IKEDA, Kozo TAKAYAMA, Tsuneji NAGAI1997 Volume 45 Issue 1 Pages 221-223
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA novel method to prepare chitosan film using a newly developed apparatus was previously reported. An electric charge supplied on the cast plate during preparation of the chitosan film produced a particular fiber arrangement of chitosan macromolecules.In this study, the drug permeation behavior was investigated in the film prepared on the metal plate loaded with electric charge (VF) in comparison with the film prepared without supplying electric charge (NVF). As model penetrants, caffeine, indomethacin and lidocaine were employed as neutral, acidic and alkaline compounds, respectively. The drug permeation through VF was significantly suppressed compared with NVF. The permeation-suppressing effect of VF was considered to be dependent on the large volume of the crystal-part in VF and fiber orientation of chitosan macromolecules in VF. The permeability coefficient for indomethacin was unusually large compared with those for caffeine and lidocaine, suggesting that the accumulation of indomethacin molecules on the surface of the chitosan films, due to an electric attraction between indomethacin and cationized chitosan molecules.View full abstractDownload PDF (470K) -
Yoshinori FUJIMOTO, Kiyoshi OHYAMA, Naoko SATO, Junko YAMADA, Masuo MO ...1997 Volume 45 Issue 1 Pages 224-226
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSChemical shifts of the diastereotopic methyl groups (C-26 and C-27) of 24-methylenecholesterol have been unambiguously assigned by synthesizing stereochemically defined 13C-labeled compounds. This allowed us to establish the steric course of hydrogen migration from C-24 to C-25 during the formation of 24-methylenecholesterol from a Δ24-precursor in a tissue culture of Catharanthus roseus.View full abstractDownload PDF (475K) -
Kyoko SATO, Yukihiro GODA, Shiho SAKAMOTO Sasaki, Hiroshi SHIBATA, Tam ...1997 Volume 45 Issue 1 Pages 227-229
Published: January 15, 1997
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSEight major pigments have been isolated from commercial Monascus pigments. The structural data on the pigments were obtained using NMR, MS, and semisyntheses. The pigments were characterized as alanine or aspartate derivatives of the orange pigments of Monascus, monascorubrin (1) and rubropunctatin (2), which have an azaphilone structure. The semisyntheses revealed that the amino acid units of the isolated compounds were the D-forms as well as the L-forms.View full abstractDownload PDF (521K)
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