All issues
Volume 37, Issue 12
Displaying 1-50 of 60 articles from this issue
-
Masami TANAKA, Yutaka ASAHI, Seizo MASUDA, Tadatoshi OTA1989 Volume 37 Issue 12 Pages 3177-3180
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe binding of phenylbutazone (PB) to bovine serum albumin (BSA) was condidered to be predominantly due to hydrophobic interaction based on the thermodynamic parameters obtained by an equilibrium dialysis method. Little variation of proton nuclear magnetic resonanc (1H-NMR) chemical shift of PB was found with change in the concentration of PB 0.5-5 mM) or upon the addition of BSA (7.25×10-5 M). The NMR spectrum of PB in 0.1 M phosphate buffer solution at pH 7 showed that PB existed as a mesomeric anion. The spin-lattice relaxation time (T1) of PB was almost concentration-independent, but decreased in the presence of BSA to 36-38% for the phenyl group and 48-100% for the butyl group. The spin-spin relaxation time (T2) of PB was also almost independent of concentration, but was remarkably decreased in the presence of BSA to ca. 2.5% for the phenyl group and ca. 6-9% for the butyl group. The ratios of the spin-relaxation rate (1/T2) of the free PB to that of the bound PB were ca. 5000-11000 for the butyl group and ca. 23000 for the phenyl group. The binding of PB to BSA was considered to involve primarily the phenyl group.View full abstractDownload PDF (629K) -
Hiroshi KASHIWAGI, Saburo ENOMOTO, Masami INOUE1989 Volume 37 Issue 12 Pages 3181-3183
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe number of radicals generated in a binary powder of glycolic acid and silica-alumina was determined by means of electron spin resonance (ESR) spectroscopy. The maximal number of spins/g and the duration of the maximal number of spins/g were dependent on the calcination temperature of silica-alumina, on conditions of storage such as atmosphere or temperature of storage, and on the particle size of silica-alumina. Each of the above values was found to be influenced significantly by mechanical force induced by shaking or compressing. Techniques for decreasing the number of radicals induced by mechanical force are discussed.View full abstractDownload PDF (610K) -
Tsuneo ITOH, Raphael G. MELIK-OHANJANIAN, Ichiro ISHIKAWA, Norio KAWAH ...1989 Volume 37 Issue 12 Pages 3184-3190
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPyrido[2, 3-d]pyrimidines were obtained by treatment of 6-allylaminouracils with PdCl2 at 60 °C, under which conditions the yields of the products were improved to a considerable extent as compared with our previously reported reaction. Pyrrolo[2, 3-d]pyrimidines were prepared under the above conditions from 6-(N-allyl-N-methylamino)uracils which were substituted with a methyl group at 6-NH of uracil. In addition, pyrido- and pyrrolo[2, 3-d]pyrimidine nucleosides were prepared from 6-(substituted allyl- or N-allyl-N-methylamino)uridines by adaptation of the above method. That is, the presence or absence of a substituent on the 6-amino group influences the size of ring formed. We proposed plausible pathways to explain why products having different ring sizes were formed.View full abstractDownload PDF (948K) -
Mieko KANARI, Masashi TOMODA, Ryoko GONDA, Noriko SHIMIZU, Miyako KIMU ...1989 Volume 37 Issue 12 Pages 3191-3194
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA neutral polysaccharide, named cinnaman AX, was isolated from the dried bark of Cinnamomum cassia BLUME. It was homogeneous on electrophoresis and gel chromatography. It is composed of L-arabinose : D-xylose in the molar ratio of 4 : 3, and its molecular weight was estimated to be about 1.0 × 106. Methylation analysis, carbon-13 nuclear magnetic resonance and controlled Smith degradation studies enabled elucidation of its structural features. It showed remarkable reticuloendothelial system-potentiating activity in a carbon clearance test.View full abstractDownload PDF (700K) -
Yasuhiro TEZUKA, Midori UEDA, Tohru KIKUCHI1989 Volume 37 Issue 12 Pages 3195-3199
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSConstituents of Spiranthes sinensis (PERS.) AMES var. amoena (M. BIEBERSON) HARA (Japanese name "nezibana") were examined and several new dihydrophenanthrenes were isolated along with orchinol (1), p-hydroxybenzaldehyde, p-hydroxybenzyl alcohol, hydrocarbons, a sterol mixture, and a ferulate mixture (5). The structures of three new dihydrophenanthrenes, spiranthol-A (2), spiranthol-B (3), and spirasineol-A (4), were determined by spectroscopic methods including two-dimensional nuclear magnetic resonance techniques. These compounds are the first examples of natural dihydrophenanthrenes containing an isopentenyl substituent.View full abstractDownload PDF (799K) -
Taisuke ITAYA, Tohru SAITO, Tsunehiro HARADA, Seiya KAGATANI, Tozo FUJ ...1989 Volume 37 Issue 12 Pages 3200-3203
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn alternative synthesis of 2', 3', 5'-tri-O-benzoyl-N, N, 3-trimethyladenosine iodide (9a) was attained by the reaction of N, N, 3-trimethyladenine (11a) with 1-O-acetyl-2, 3, 5-tri-O-benzoyl-β-D-ribofuranose (10) in the presence of SnCl4 followed by treatment with NaI. Although 3-benzyl-N, N-dimethyladenine (11c) did not react with under similar conditions, the ribosylation of 3-ethyl-N, N-dimethyladenine (11b) followed by alkaline hydrolysis led to the first synthesis of 5-(ethylamino)-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamide (15b). A more general procedure for the synthesis of 5-(alkylamino)-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamides (15) was developed via a series of reactions : alkylation of N'-benzyloxy-5-formamido-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamidine (12) with alkyl halides in the presence of K2 CO3, catalytic hydrogenolysis, and alkaline hydrolysis. By means of this method, 5-(benzylamino)- (15c) and 5-(isopropylamino)-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamide (15d) were synthesized for the first time.View full abstractDownload PDF (749K) -
Masaru SENUMA, Masataka SHIBAZAKI, Shigeru NISHIMOTO, Keijiroh SHIBATA ...1989 Volume 37 Issue 12 Pages 3204-3208
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPractical resolution of (2RS, 3RS)-2-hydroxy-3-(4-methoxyphenyl)-3-(2-nitrophenylthio)propionic acid (2) was examined by the use of several basic amino acids. L-Lysine was found to be the most effective resolving agent to obtain (+)-(2S, 3S)-2, a key intermediate for the synthesis of diltiazem (1). This new method should be applicable to the industrial production of 1 in view of the simplicity of the procedure, the ready availability of L-lysine, and the high yield of the desired isomer. The absolute stereochemistry of (+)-2 was determined to be 2S, 3S by X-ray crystallographic analysis.View full abstractDownload PDF (673K) -
Masateru ONO, Toshio KAWASAKI, Kazumoto MIYAHARA1989 Volume 37 Issue 12 Pages 3209-3213
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAlkaline hydrolysis of the ether-soluble resin glycoside ("jalapin") fraction of the roots of Ipomoea operculata (Convolvulaceae) gave five glycosidic acids, operculinic acids A (1), B (2), C (3), D and E, along with n-decanoic and n-dodecanoic acids. Operculinic acids A, B and C were characterized to be 11S-jalapinolic acid 11-O-β-D-glucopyranosyl-(1→3)-O-[α-L-rhamnopyranosyl-(1→4)]-O-α-L-rhmnopyranosyl-(1→4)-O-α-L-rhamnopyranosyl-(1→2)-β-D-fucopyranoside, 11S-jalapinolic acid 11-O-β-D-glucopyranosyl-(1→3)-O-[α-L-rhamnopyranosyl-(1→4)]-O-α-L-rhamnopyranosyl-(1→4)-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside and 11S-jalapinolic acid 11-O-α-L-rhamnopyranosyl-(1→4)-O-α-L-rhamnopyranosyl-(1→4)-O-α-L-rhamnopyranosyl-(1→2)-β-D-fucopy6ranoside, respectively, on the basis of chemical and spectroscopic data.n-Decanoic and n-dodecasnoic acids found in this study are the first component organic acids of the resin glycosides so far studied.View full abstractDownload PDF (836K) -
Shigetoshi KADOTA, NZUNZU LAMI, Yasuhiro TEZUKA, Tohru KIKUCHI1989 Volume 37 Issue 12 Pages 3214-3220
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSExamination of the ether extract of the roots of Boerhaavia diffusa L. led to the isolation of three new rotenoid analogues along with fatty acids, glycerides, and sterol derivatives. The structures of two rotenoid analogues named boeravinone A and boeravinone B have been determined by means of nuclear magnetic resonance spectroscopy including two-dimensional incredible natural abundance double quantum transfer experiment (2D INADEQUATE) and 1H-13C long range correlation spectroscopy.View full abstractDownload PDF (1006K) -
Masao ARIMOTO, Hideo YAMAGUCHI, Eiichi FUJITA, Yoshimitsu NAGAO, Masah ...1989 Volume 37 Issue 12 Pages 3221-3224
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSReaction of Allyltrimethylsilanes with iodosylbenzene and trimethylsilyl azide in dichloromethane at -78 °C to room temperature affords vicinal diazides, which undergo fluoride ion-catalyzed β-elimination of azide and trimethylsilyl groups, providing allyl azides in good yields.View full abstractDownload PDF (694K) -
Tokujiro KITAGAWA, Hiroko KURODA, Keiko IIDA, Miyuki ITO, Miwa NAKAMUR ...1989 Volume 37 Issue 12 Pages 3225-3228
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPotassium salts (22) of various carboxylic acids readily react with 2, 2'-oxalyldi(2, 3-dihydro-3-oxobenzisosulfonazole) (17) to form the corresponding 2-acyl-2, 3-dihydro-3-oxobenzisosulfonazoles (24) as intermediates, which undergo aminolysis, alcoholysis, and thioalcoholysis to afforded amides (5), esters (6), and thioesters (7), respectively. These findings show that 17 can be conveniently used as a condensing agent for the synthesis of carboxylic acid derivatives (5, 6 or 7).View full abstractDownload PDF (568K) -
Kunizo ARAI, Hisae MIYAJIMA, Taisei MUSHIRODA, Yuzuru YAMAMOTO1989 Volume 37 Issue 12 Pages 3229-3235
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFour new metabolites, italicic acid, dihydro-italicic acid, methyl italicate and italicinic acid, were isolated from culture medium of Penicillium italicum WEHMER. The structures, possessing a 4-ylidene-acyltetronic acid unit, and their biosynthesis were elucidated. Two other new metabolites possessing a chromone skeleton were also isolated and their structures were established as 6, 7-dihydroxy-3-(1'-hydroxy-3'-butanoyl)chromone-5-carboxylic acid and its 1', 2'-dehydrate.View full abstractDownload PDF (1098K) -
Kimiaki ISOBE, Chie MOHRI, Hiromichi SANO, Kunihiko MOHRI, Hiroshi ENO ...1989 Volume 37 Issue 12 Pages 3236-3238
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new dioxopyrroline, 4, 5-diethoxycarbonyl-1H-pyrrole-2, 3-dione (3), was proved to be a strong dienophile in the Diels-Alder reaction with various butadienes. This cycloaddition reaction proceeded in a regio- and stereo-selective manner to give the polyfunctionalized hydroindoles (4-8, 10) which may be potential synthetic intermediates of Erythrina alkaloids.View full abstractDownload PDF (545K) -
Yoshifumi MAKI, Iwao OYABU, Seiji OHARA, Magoichi SAKO, Yukio KITADE, ...1989 Volume 37 Issue 12 Pages 3239-3242
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIrradiation of indole-3-acetic acid (2) in the presence of pyrimido[5, 4-g]pteridine N-oxide (1a) results in the formation of indole-3-carboxyaldehyde (3) as a major product. A reaction sequence for the photooxidative decarboxylation is presented and discussed in connection with the biological transformation of 2 to 3 in plants.View full abstractDownload PDF (626K) -
Tozo FUJII, Tohru SAITO, Tsuyoshi NAKASAKA1989 Volume 37 Issue 12 Pages 3243-3246
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSIn order to investigate the effects of the N(3)- and N(9)-substituents in 3, 9-disubstituted adenines on the stability of the adenine ring, the equilibrium constants and the rates of ring opening and cyclization for the equilibria between the 3, 9-disubstituted adenines IVa-l and the N-alkylformamidoimidazoles Va-l in H2O at pH 8.98 and 25 °C have been measured. A bulky substituent at the 3-position of IV has been found to retard the ring opening leading to V, whereas an electron-withdrawing group at the 3- or 9-position accelerates it. A bulky alkyl group on the formamido nitrogen of V markedly retards the cyclization leading to IV, favoring the ring-opened form in the equilibrated mixture. Syntheses of 3-isopropyl-9-methyladenine perchlorate (IVc) and 3-(4-methoxybenzyl)-9-methyladenine perchlorate (IVe), required for the kinetic study as substrates, are also described.View full abstractDownload PDF (692K) -
Akira TAKAHASHI, Genjiro KUSANO, Tomihisa OHTA, Yasushi OHIZUMI, Shige ...1989 Volume 37 Issue 12 Pages 3247-3250
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThree new fasciculol esters, fasciculic acids A (1), B (2) and C (3), having potent calmodulin antagonistic activity were isolated from the toxic mushroom Naematoloma fasciculare (Fr.) KARST. Their structures were elucidated on the basis of spectral and chemical evidence.View full abstractDownload PDF (639K) -
Chun-Jie SHAO, Ryoji KASAI, Kazuhiro OHTANI, Jing-Da XU, Osamu TANAKA1989 Volume 37 Issue 12 Pages 3251-3254
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFrom leaves of Kalopanax septemlobus (THUNB.) KOIDZ., three new saponins named kalopanax-saponins La (6), Lb (7) and Lc (8) were isolated together with five known saponins, kalopanax-saponins A and B, akeboside Stb, eleutheroside K and saponin Pg. The new sapogenin 9 named kalopanax-genin L1, which is common to 6, 7 and 8, was formulated as 22α-hydroxyhederagenin. On the basis of chemical and spectral data, the structures of these saponins were elucidated as follows : 3-O-α-L-arabinopyranosyl-22α-hydroxyhederagenin (6), 3-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl-22α-hydroxyhederagenin (7) and 3-O-β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl-22α-hydroxyhederagenin (8).View full abstractDownload PDF (606K) -
Fumio HASHIMOTO, Gen-ichiro NONAKA, Itsuo NISHIOKA1989 Volume 37 Issue 12 Pages 3255-3263
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA chemical examination of the polypenolic constituents in commercial oolong tea has led to the isolation of a new-flavan-3-ol, two novel dimeric flavan-3-ols named oolonghomobisflavans A and B eight new proanthocyanidins, together with twenty-one known polyphenols including proanthocyanidins, hydrolyzable tannins and red pigments. On the basis of chemical and spectroscopic evidence, the flavan-3-ol has been characterized as 8-C-ascorbyl (-)-epigallocatechin 3-O-gallate (22), while oolonghomobisflavans A (26) and B (27) have been determined to be dimeric flavan-3-ols in which two units are linked through a methylene bridge at the 8, 8'- and 8, 6'-positions, respectively. The structures of the new proanthocyanidins were elucidated mainly by tannase hydrolysis and thiolytic degradtion as epicatechin-(4β→8)-epigallocatechin 3-O-gallate (29), epicatechin 3-O-gallate-(4β→8)-epigallocatechin 3-O-gallate (30), catechin-(4α→8)-epigallocatechin 3-O-gallate (31), prodelphinidin B-4 3'-O-gallate (32), epicatechin 3-O-gallate-(4β→6)-epigallocatechin 3-O-gallate (33), epigallocatechin 3-O-gallate-(4β→6)-epicatechin 3-O-gallate (34), epiafzelechin 3-O-gallate-(4β→6)-epigallocatechin 3-O-gallate (35) and prodelphinidin B-2 3'-O-gallate (36).View full abstractDownload PDF (1228K) -
Miyoji HANAOKA, Shuji YOSHIDA, Chisato MUKAI1989 Volume 37 Issue 12 Pages 3264-3267
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe Wittig reaction of 8, 14-cycloberbin-13-ones (4), derived from the corresponding protoberberine alkaloids (2), with methylenetriphenylphosphorane afforded 13-methylene-8, 14-cycloberbines (5). Irradiation of 5 with a 100 W high pressure mercury lamp effected photochemically-induced electrocyclic fission of the aziridine ring to yield 13-methylberberine (1a), dehydrocorydaline (1b), and corysamine (1c) in high yield. Introduction of ethyl and propyl groups on the C-13 position in 2 was also conveniently achieved via photochemical reaction of the corresponding alkylidene derivatives (8 and 9, respectively).View full abstractDownload PDF (728K) -
Hideko KAWAKI, Yoshio SASAKI, Tatsuya TAKAGI, Shiho FUJII, Fumika MASU ...1989 Volume 37 Issue 12 Pages 3268-3271
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSFor di-and trisubstituted benzene derivatives, the novel quantitative structure-activity relationships descriptors σS°, representing both dispersion and repulsion interaction energies, have been successfully determined from the linear relations of the observed absolute entropy S°298(g) for the above series against those of monosubstituted benzene derivatives, Unknown values of S°298(g) could be estimated statistically by inter- or extrapolation of the linear relations, and numerous kinds of descriptors, σS° for ortho-, meta-, para-disubstituted benzene derivatives, together with those of the trisubstituted series, having the same kind of substituent, have been presented.Their validities are supported by the results of evaluation of the gas liquid chromatography relative retention value logγ for disubstituted benzene derivatives.View full abstractDownload PDF (598K) -
Masao MIYAUCHI, Takashi HIROTA, Koichi FUJIMOTO, Junya IDE1989 Volume 37 Issue 12 Pages 3272-3276
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe effect of the C-3 substituent on the oral absorbability of pivaloyloxymethyl (POM) ester of cephalosporin in mice is described. The C-3 substituent affects the physicochemical and biochemical properties of POM ester, such as lipophilicity, water solubility, chemical stability and enzymatic stability. Quantitative analyses of the relationships between these properties and the oral bioavailability have been attempted.Lipophilicity made a parabolic contribution to the absorption. The optimum log Poctanol/water value was estimated to be around 2.22. The chemical isomerization of the cephem double bond from Δ3 to Δ2 in the intestinal lumen prior to absorption contributed linearly to decrease of absorption. In the case of POM ester having a larger isomerization rate, more Δ2 isomer was detected in feces and urine. Enzymatic hydrolysis of POM ester to the parent acid in intestinal tissue was faster for a more lipophilic ester. Hydrolytic activity, which was detected in the content of the intestinal lumen, would lower the absorption. The effect of the C-3 substituent on water solubility was not important for the absorption of cephalosporin employed in the present study.Isomerization of the double band, which was found to be characteristic for cephalosporin ester, prosented a problem in the prodrug approach for oral use.View full abstractDownload PDF (721K) -
Kiyoshi UKAWA, Eiko IMAMIYA, HIroaki YAMAMOTO, Tetsuya AONO, Yoshio KO ...1989 Volume 37 Issue 12 Pages 3277-3285
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new series of amphiphilic 1-octadecyl glycerolipids (eleven compounds, 1a-k) were designed and synthesized, in which the 3-phosphocholine portion of platelet-activating factor (1-alkyl-2-acetyl-sn-glycero-3-phosphocholine, PAF) was replaced by the 2-(2-trimethylammonioethoxy)ethyl group and congeneric groups having oligo(ethyleneoxy)ethyl bridges of various lengths at position 3, together with modification at position 2 (lower alkyl, acetonyl, acetoacetyl, carboxymethyl and pyrimidin-2-yl groups). These ether lipids, characterized by a nonphosphorus lysoglycerolipid structure, showed potent antitumor activity in vitro (human promyelocytic leukemia cells, HL-60, and human epidermoid carcinoma cells, KB) and in vivo (mouse sarcoma S180 and mouse mammary carcinoma MM46). Maximal in vitro potency was obtained with 1-O-octadecyl-2-O-(2-pyrimidinyl)-3-O-[2-(2-trimethylammonioethoxy)ethyl]glycerol (1g; IC50 values for both HL-60 and KB were 0.32 μg/ml, indicating a higher activity than alkyl-lysophospholipid, ET18-OMe). Several appropriately 2-substituted 1-octadecylglycerolipids with the 3-[2-(2-trimethylammonioethoxy)ethyl]group (e.g., methyl, 1b; butyl, 1f; 2, 2, 2-trifluoroethyl, 1g; and acetonyl, 1k) showed a potent life-span-prolonging effect on mice with ascites sarcoma S180 and on those with mammary carcinoma MM46, when administered intraperitoneally at 16.5 and 12.5 mg/kg/d, respectively. Compounds 1b and 1k showed definite tumor growth inhibition against solid sarcoma S180 in mice, whether given p.o. or i.v. at 16.5 gm/kg/d. Studies on the structure-activity relationships indicate that the metabolic stability to phospholipase C or related enzymes is at least partly responsible for the potent antitumor activity of this series of ether lipids.View full abstractDownload PDF (1535K) -
Morihiro MITSUKUCHI, Tomoyuki IKEMOTO, Minoru TAGUCHI, Shohei HIGUCHI, ...1989 Volume 37 Issue 12 Pages 3286-3293
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of 21-thio derivatives of 9α-fluoro-11β, 17α-dihydroxy-16β-methyl-1, 4-pregnadiene-3, 20-dione 17-esters and related compounds were synthesized and evaluated as topical antiinflammatory agents. These compounds were prepared by the reaction of 9α-fluoro-11β, 17α, 21-trihydroxy-16β-methyl-1, 4-pregnadiene-3, 20-dione (betamethasone, I) 17-ester derivatives and various mercapto compounds. A structure-activity relationship study revealed that the structural combination of a thio group at the 21-position and an ester group at the 17-position contributed to vasoconstrictive activity. Among these compounds, the 21-methylthio 17-propanoate compound (6) was found to have the most potent activity, being more potent than betamethasone 17-valerate (BV).View full abstractDownload PDF (1211K) -
Hahn DUFAT-TRINH VAN, Elisabeth SEGUIN, Francois TILLEQUIN, Claude MON ...1989 Volume 37 Issue 12 Pages 3294-3300
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSRacemic 7-hydroxy-9-oxa anthracyclinone (5a) has been synthetised in seven steps from quinizarin (6) and its resolution achieved after glycosylation with 3, 4-di-O-acetyl-2-deoxy-L-fucose. Chiral pool syntheses of (8S)-8-hydroxymethyl-9-oxa-anthracyclinone (5b) and of (8S, 10R) and (8S, 10S)-8-hydroxymethyl-10-methyl-9-oxa-anthracyclinones (5c and 5d) have been achieved using (R)-2, 3-O-isopropylideneglyceraldehyde (12) and leucoquinizarin (13) as starting materials. Glycosylation of aglycones 5b-5d by either 3, 4-di-O-acetyl-2-deoxy-L-fucose or various 3-amino-2, 3, 6-trideoxy-L-hexoses yielded the corresponding anthracyclines. The synthetic glycosides do not show significant cytotoxic activity at a concentration of 1 μg/ml against L 1210 cells.View full abstractDownload PDF (1236K) -
Kiyoshi YOSHINARI, Yutaka SASHIDA, Hiroko SHIMOMURA1989 Volume 37 Issue 12 Pages 3301-3303
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPhytochemical examinations of the barks of Prunus species have led to the isolation of two new lignan xylosides, ssioriside (9) and prupaside (12). Compound 9 was obtained from Prunus (P.) ssiori and P. padus and 12 from P. padus. The spectroscopic data and chemical evidence allowed assignment of the structures of 9 and 12 as (8S, 8'S)-4, 4'-dihydroxy-3, 5, 3', 5'-tetramethoxy-8-8'-butyrolignan 9-O-β-D xylopyranoside and (8R, 7S, 8'R)-5, 5'-dimethoxylari-ciresinol 9'-O-β-D-xylopyranoside, respectively. Several previously reported compounds were also obtained and identified.View full abstractDownload PDF (611K) -
Hiroshiau KOHDA, Osamu TAKEDA, Seiji TANAKA1989 Volume 37 Issue 12 Pages 3304-3305
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe main molluscicidal activity of the methanol extract of Lysimachia sikokiana is due to several triterpenic saponins called sakuraso-saponins. The most active component was isolated from the aerial parts and elucidated as 3-O-β-xylopyranosyl-(1→2)-β-glucopyranosyl-(1→4)-[β-glucopyranosyl-(1→2)]-α-arabionopyranosyl protoprimulagenin A, named lysikoianoside 1, on the basis of 1H- and 13C-nuclear magnetic resonance spectral data and methylation analysis results.View full abstractDownload PDF (502K) -
Mitsuhiko NOSE, Sakae AMAGAYA, Yukio OGIHARA1989 Volume 37 Issue 12 Pages 3306-3310
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe hemolytic properties and the adsorbability on red blood cells of saikosaponin a, saikosaponin d and 13 metabolites formed in the alimentary tract were investigated. Among these compounds, saikosaponin d and its intestinal product, prosaikogenin G, which possess an α-hydroxyl function at C16, showed the strongest hemolytic activity at the dose range of 1.0 to 5.0 μg/ml. Saikosaponin a and its intestinal product, prosaikogenin F, which possess a β-hydroxyl function at C16, showed activity above 10 μg/ml. In this case, the monoglycoside, prosaikogenin F, showed the stronger activity than the diglycoside, saikosaponin a. Among the gastric products whose ether ring was cleaved to produce a carbinol, the monoglycosides, prosaikogenin A and prosaikogenin H, showed a slight activity above 25 μg/ml, and the saikogenins except saikogenin A were inactive. Saikogenin A, however, had hemolytic activity at a dose of 15 μg/ml. The adsorbabilities of these compounds on red blood cell membranes closely paralleled their degrees of hemolytic activity.View full abstractDownload PDF (671K) -
Nobuko SAKURAI, Shin-ichi NAGASHIMA, Ken-ichi KAWAI, Takao INOUE1989 Volume 37 Issue 12 Pages 3311-3315
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA new tetrahydrofuranoid lignan, named (-)-berchemol (1), mp 188-189 °C, [α] D -7.9°, C20H24O7, was isolated together with a known lignan, (-)-secoisolariciresinol, from the stems of Berchemia racemosa SIEB. et ZUCC. (Rhamnaceae). The relative stereostructure of 1 was elucidated on the basis of chemical evidence, and spectroscopic and X-ray analysis. The absolute configuration of 1 was determined by comparison of its circular dichroism spectrum with that of (-)-olivil. (-)-Berchemol was determined to be (2R, 3S, 4S)-2, 4-bis(4-hydroxy-3-methoxyphenyl)-3-hydroxy-3-hydroxymethyltetrahydrofuran.View full abstractDownload PDF (724K) -
Chieh-Wu CHEN, Yumiko SAKAI, Yasushi HASEBE, Jun-ichi ANZAI, Akihiko U ...1989 Volume 37 Issue 12 Pages 3316-3319
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSPhoto-switchable ion and enzyme sensors were fabricated by the use of glassy carbon electrode coated with nonactin-doped or enzyme modified poly(vinyl chloride) (PVC) embranes. The ion sensor with nonactin-doped PVC membrane, which contained spirobenzopyran as the photosensitive dye, exhibited a potentiometric photoresponse to NH4+ ion in the solution. The dynamic range of the NH4+ ion sensor was 10-7-10-3 M. Urea, adenosine, and asparagine sensors were prepared by coating the surface of the NH4+-ion sensor with urease, adenosine deaminase, and asparaginase membranes, respectively. These enzyme sensors could be used for determining the substrates at the micro mole level. The performance characteristics of these sensors were compared with those previously prepared membrane electrode sensors.View full abstractDownload PDF (567K) -
Jun-ichi ANZAI, Shouryu LEE, Tetsuo OSA1989 Volume 37 Issue 12 Pages 3320-3322
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA highly branched polyethyleneimine (PEI) was used as a spacer for immobilizing α-chymotrypsin on the surface of Langmuir-Blodgett (LB) membranes which were deposited on the gate of an ion-sensitive field effect transistor (ISFET). α-Chymotrypsin could be covalently immobilized through the glutaraldehyde-activated PEI on the LB membrane-coated ISFET. The α-chymotrypsin-modified ISFET showed a potentiometric response to the substrate at concentrations of more than 0.1 mM. Some performance characteristics of the sensor, such as pH response, response time, and long-term stability were examined.View full abstractDownload PDF (484K) -
Takashi IIDA, Toshiaki MOMOSE, Frederic C. CHANG, Junichi GOTO, Tosio ...1989 Volume 37 Issue 12 Pages 3323-3329
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe 4β-hydroxylated derivatives of lithocholic, deoxycholic, chenodeoxycholic, and cholic acids were synthesized from their respective parent compounds. The principal reactions employed were 1) β-face cis-dihydroxylation of Δ3 intermediates with osmium tetroxide-N-methylmorpholine N-oxide, 2) selective cathylation of vicinal 3β, 4β-diols followed by oxidation of the resulting 4β-monocathylates, or direct selective oxidation at C-3 of 3β, 4β-diols with pyridinium chlorochromate, and 3) stereoselective reduction of the 3-oxo compounds with tert-butylamine-borane complex. The results of analysis of the prepared 4β-hydroxylated bile acids with a diequatorial trans-glycol structure and their 3β-epimers by proton and carbon-13 nuclear magnetic resonance spectroscopies are briefly discussed along with the mass spectrometric properties.View full abstractDownload PDF (1157K) -
Akira SANO, Naoto TAKIMOTO, Shoji TAKITANI1989 Volume 37 Issue 12 Pages 3330-3332
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA fluorometric method for the assay of nicotinamide methyltransferase has been established using rat liver 9000 × g supernatant fluid as a model enzyme preparation. 1, 4-Dimethylnicotinamide formed enzymatically from a new substrate, 4-methylnicotinamide, is quantified by means of its fluorescence reaction with 4-methoxybenzaldehyde in aqueous alkali. The lower limit of determination of 1, 4-dimethylnicotinamide is 100 pmol in the enzymatic reaction mixture. The apparentKm values for 4-methylnicotinamide and for nicotinamide, which is a known substrate for this enzyme, were 0.19 and 0.13 mM, respectively, whereas the relative activity of 4-methylnicotinamide as a methyl acceptor was about 1.5 times the value of nicotinamide.View full abstractDownload PDF (583K) -
Toshihiro AIUCHI, Masami MATSUNAGA, Kazuyasu NAKAYA, Yasuharu NAKAMURA1989 Volume 37 Issue 12 Pages 3333-3337
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTo estimate membrane potential in synaptosomes with the use of tetraphenylphosphonium (TPP+), an equation relating the amount of TPP+ accumulated in synaptosomes with membrane potential was derived from the following two assumptions. (1) TPP+ molecules were distributed into plasma membranes, mitochondria and cytosol of synaptosomes. (2) TPP+ achieves a Nernst equilibrium across both the synaptosomal and inner mitochondrial membranes. We propose three methods for calculation of membrane potential using this equation. The concentration of TPP+ was measured under various controlled conditions with an electrode selective for TPP+. The amount of TPP+ accumulated in synaptosomes was determined by measuring the difference between its initial concentration and the concentration after addition of synaptosomes, and membrane potential was estimated by the three methods. The resting potential of synaptosomes was estimated to be -75 to -90 mV by all of these methods. Membrane potentials under various controlled conditions were calculated, and the characteristics of the methods for estimation of membrane potential and those of membrane potential obtained by the methods are discussed.View full abstractDownload PDF (790K) -
Yorishige IMAMURA, Yoshihide NOZAKI, Masaki OTAGIRI1989 Volume 37 Issue 12 Pages 3338-3342
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn enzyme (befunolol reductase) which catalyzes the reduction of befunolol to dihydrobefunolol was purified from the cytosolic fraction of rabbit liver to homogeneity by various chromatographic techniques. Befunolol reductase had molecular weights of 29000 on sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and 34000 on gel filtration. The enzyme required reduced nicotinamide adenine dinucleotide phosphate (NADPH) as a cofactor and showed an optimal pH of 6.5. The apparent Km and Vmax values of the enzyme for the reduction of befunolol were 1.7 mM and 4.4 units/mg, respectively. Flavonoids, sulfhydryl reagents, heavy metals and coumarins strongly inhibited the enzyme. The enzyme catalyzed the reduction of a variety of aromatic ketones. In addition to befunolol, some ketone-containing drugs such as daunorubicin and levobunolol were efficiently reduced by the enzyme. On the basis of substrate specificities for steroids, befunolol rductase purified from the cytosolic fraction of rabbit liver appeared to be a 3α-hydroxysteroid dehydrogenase.View full abstractDownload PDF (1003K) -
Masatoshi YAMAZAKI, Jun KISUGI, Hisao KAMIYA1989 Volume 37 Issue 12 Pages 3343-3346
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAn anti-neoplastic factor, dolabellanin A, inducing tumor lysis was purified from the albumen gland of a sea hare, Dolabella auricularia. Purified dolabellanin A was found to be a glycoprotein of 250 kilodaltons containing 4 subunits. This factor was half-maximally active towords a variety of tumor cells at 1-18 ng protein/ml and lysed tumor necrosis factor (TNF)-resistant tumor cells. Dolabellanin A was labile on heating, at low and high pH, and on treatment with urea, guanidine, sodium lauryl sulfate or trypsin, but not with 2-mercaptoethanol or periodate. Dolabellanin A completely inhibited the syntheses of deoxyribonucleic acid and ribonucleic acid by tumor cells within 1 h and caused their complete cytolysis within 18 h. Tumor lysis by dolabellanin A was not inhibited by anti-TNF antibody but was inhibited by certain sugars, suggesting that recognition of a sugar moiety is a key step in its induction of cytolysis.Dolabellanin A also prolonged the survival of mice bearing syngneic MM46 ascitic tumors (p<0.001). These results suggest that dolabellanin A, found in an invertebrate, the sea hare, is a new antitumor factor.View full abstractDownload PDF (700K) -
Hiroteru SAYO, Masako SAITO, Eibai LEE, Kimio KARIYA1989 Volume 37 Issue 12 Pages 3347-3350
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAlthough in the absence of halide ion chloroperoxidase did not catalyze the ethylhydroperoxide (EHP)-supported oxidation of aminopyrine, in the presence of Br- or Cl-, chloroperoxidase did catalyze the oxidation of aminopyrine, generating the aminopyrine cation radical (AP+). The initial rate of AP+ formation was determined by monitoring the absorbance at 565 nm. The pH optimum of the reaction was centered around 5.0. The rate of AP+ formation showed typical Michaelis-Menten saturation kinetics with respect to EHP, aminopyrine and Br-. The rate of formation of bromine in the chloroperoxidase-EHP-Br- system was also determined by measuring the changein absorbance at 267 nm. In the system containing 1 mM EHP and 0.2 M KBr at pH 5.0, the rate was 1.8 nmol of bromine/s/μg of chloroperoxidase, which was slower than that of AP+ formation under the same conditions. The present results suggest that tha formation of AP+ is initiated by the halogenation of the N, N-dimethylamino group followed by the homolysis of the haloammonium cation, and that tha most likely halogenating reagent is an enzyme-bound halogenating intermediate.View full abstractDownload PDF (629K) -
Kunihiko MORITA, Masayuki YAMAKAWA, Tokuzo MINOUCHI, Yukio HAYASHI, No ...1989 Volume 37 Issue 12 Pages 3351-3354
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe change in the hepatic oxidative drug-metabolizing capacity in humans treated with ozagrel hydrochloride monohydrate (OZA), an imidazole derivative and a new thromboxane A2 synthase inhibitor, was studied and the inhibitory potencies of the metabolites of OZA (M-1 and M-2) on the mouse hepatic microsomal monooxygenase system in vitro were compared with that of OZA.In vitro, M-1 and M-2, which are the βoxidized form and the reduced form of OZA, respectively, inhibited aminopyrine N-demethylation, aniline hydroxylation and testosterone hydroxylations in mouse hepatic microsomes and produced type II difference spectra in the same manner as OZA, The kinetic data indicated that the inhibitory potencies and the affinities of these compounds for cytochrome P-450 were decreased in the order of M-2>OZA>M-1.The ratio of 6β-hydroxycortisol (6β-OHF) to cortisol (F) in urine, used as an indicator of oxidative drug-metabolizing capacity in humans, did not change significantly during oral treatment with 400 mg/d of OZA, while the ratio decreased to 80-85% of the original level during treatment with 800 mg/d of OZA. Although the participation of the metabolites of OZA in the reduction of drug-metabolizing capacity in vivo is not yet clear, the results suggest that hepatic oxidative drug-metabolizing enzyme activities in humans are inhibited by treatment with a relatively high dose of OZA.View full abstractDownload PDF (676K) -
Hisakazu SUNADA, Yumiko TAKAHASHI, Takashi KURIMOTO, Yoshiko HIRAI, Yo ...1989 Volume 37 Issue 12 Pages 3355-3358
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSGranulated stearyl alcohol was dispersed on the surface of aqueous media in the presence of sodium lauryl sulfate (SLS : 0-0.50 [g/100 ml]). The changes of the shape factors, the average contact numbers and the porosities during flocculation were examined. The particles on the surface of the water without SLS formed more dendric and more porous agglomerates than those on the surface of solutions with SLS (0.25-0.50 [g/100 ml]). The particles on the former surface showed strong hydrophobic bonding (particle/particle bonding) and a higher coefficient of internal friction, measured in the shearing test. So, they were relatively rigid after the initial flocculation. On the other hand, the agglomerate particles adsorbed with SLS on the latter surface showed weak bonding between particles and a lower friction coefficient. So, their agglomerate structure changed with time, forming rounder and more compact agglomerates.View full abstractDownload PDF (593K) -
Takayuki OHWAKI, Masaaki ISHII, Shigeru AOKI, Kimio TATSUISHI, Masanor ...1989 Volume 37 Issue 12 Pages 3359-3362
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSNasal absorption of secretin in rats was enhanced in an acid solution and the maximum absorption was observed at a sodium chloride solution molarity of 0.462. In order to predict how changes in the secretin molecule would affect its absorption through the nasal mucosa independently of structural changes in the epithelial membrane, and artificial membrane permeation test was conducted, and the apparent partition coefficient between octanol and a test solution was determined. The concentration of secretin was measured using high performance liquid chromatography. The amount of secretin that permeated through an artificial membrane was hardly affected by changes in pH, which suggested taht the size of the secretin molecule was not changed. The apparent partition coefficient, however, increased as the pH of the test solution rose from 3.81 to 7.0, which suggested that the hydrophobicity of secretin was enhanced. In relation to the osmolarity of the test solution, the amount of permeation was hardly affected by the concentration of sodium chloride, but the partition coefficient increased with the concentration of the sodium chloride solution. It was supposed that the size of the secretin molecule was not changed in spite of the increasing hydrophobicity, and the nasal absorption of secretin at a sodium chloride molarity of 0.462 was dependent on a change in the epithelial cells. When sorbitol was used as an osmoregulatory agent, the apparent partition coefficient hardly varied as the osmolarity of the solution was increased, whereas the amount of permeation decreased, and these findings reflected the nasal absorption in rats.View full abstractDownload PDF (685K) -
Eiji YUKAWA, Shun HIGUCHI, Toshinobu AOYAMA1989 Volume 37 Issue 12 Pages 3363-3366
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSWe investigated the influence of the population pharmacokinetic parameters on the performance of the Bayesian feedback method in predicting the phenytoin (PHT) dosage needed to achieve a desird PHT serum concentration. Population pharmacokinetic parameters studied were taken from reports by Sheiner et al. (I), Grasela et al. (II), Miller et al. (III), and the authors (IV). The predictive abilities of the Bayesian feedback method were evaluated by using retrospective data from 70 patients. The mean prediction error, mean absolute prediction error (MAE), and root mean squared error (RMSE) served as measures of prediction bias and precision.The precision of the initial estimates based on the population parameter set IV was superior to those of other initial estimates studied. The performance of the Bayesian feedback method to predict PHT dosage at the steady state was relatively insensitive to bias in the estimates of the population parameters. However, the revised estimates derived from the Bayesian feedback method using the population parameter set IV with one feedback gave the lowest MAE and RMSE in predicting PHT dosage.View full abstractDownload PDF (615K) -
Kenji UKITA, Minoru KURODA, Hirotaka HONDA, Masumi KOISHI1989 Volume 37 Issue 12 Pages 3367-3371
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA novel powder particle, nominated as powder-coated microsponge (PMS) containing sunset yellow (SY), was prepared by dry impact blending, and the subsequent dissolution behavior of SY from PMS was studied. Two kinds of spherical and porous cellulose particles known as microsponge (10.3 or 53.9 μm in volume-surface mean diameter) containing SY were coated with spherical polymethylmethacrylate particles (PMMA, 0.15 or 0.40 μm in diameter) and titanium dioxide particles (anatase-type, 0.25 μm in diameter). This coating was carried out without solvents. The angle of repose and the bulkiness of PMS were largely dependent on the amount of PMMA. The dissolution rate of SY from PMS decreased greatly as the amount of PMMA was increased, and was also influenced by the particle size of the microsponges and PMMA, but its correlation with the coating amount of titanium dioxide was very poor. On the basis of these results, a novel preparation of a micron-order offering a controllable release of ingredients is proposed.View full abstractDownload PDF (1203K) -
Ichimaro YAMADA, Tomoko GODA, Miwako KAWATA, Hiroaki MIZUTA, Kenji OGA ...1989 Volume 37 Issue 12 Pages 3372-3375
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe effect of gastric acidity on the bioavailability of N, N-dimethylcarbomoylmethyl α, 2-dimethyl-5H-[1]benzopyrano[2, 3-b]pyridine-7-acetate (1), a new anti-inflammatory agent, was investigated in gastric acidity-controlled beagle dogs.The dissolution rates of this compound in media of pH 1.2 and 3.0 were greater than those in media of pH 5.0 and 6.8. Reflecting these dissolution characteristics, the peak plasma concentration (Cmax) and the area under the plasma concentration-time curve (AUC0-12h) were rduced by shifting the gastric acidity to low levels (more than pH 6) with omeprazole treatmen.In designing dosage forms of 1, it is necessary to develop pharmaceutical preparations whose bioavailability is not affeted by the gastric acidity.View full abstractDownload PDF (618K) -
Hitoshi NAKAMURA, Kiyoto EDO, Takanori HISHINUMA, Toshihiro TAKAHASHI, ...1989 Volume 37 Issue 12 Pages 3376-3379
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA tricyclic antidepressant, 11C-labeled imipramine was synthesized by N-methylation of desipramine with 11CH3I to assist in the imaging of the human imipramine receptor by positron emission tomography. The radiochemical yield after purification of 11C-imipramine by high performance liquid chromatography was 28-63% at a specific activity of 26-53 Ci/mmol. The time required for synthesis, including purification was 30 min from the end of 11CH3I trapping. The organ distribution of 11C-imipramine was investigated in mice at various times after i.v. injection. The main accumulation of radioactivity was in the kidney, followed by the lung and the heart. In the brain, the radioactivity levels in the hypothalamus and striatum were the highest and remained constant, differentiating them from other portions of the brain. Furthermore, the result of a binding assay with 3H-labeled imipramine suggested that the regional distribution fo 11C-imipramine in the same mouse brain correlated to that of the high affinity imipramine binding site.View full abstractDownload PDF (631K) -
Shigeyuki YOSHIFUJI, Yukimi ARAKAWA1989 Volume 37 Issue 12 Pages 3380-3381
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSRuthenium tetroxide (RuO4) oxidation of 3, 4-dihydroisoquinolin-1(2H)-ones produced the corresponding isoquinoline-1, 3, 4(2H)-triones in good yields. In the cases of N-alkyl derivatives having two oxidation sites adjacent to the nitrogen atom, regioselective endocyclic oxidation was observed.View full abstractDownload PDF (445K) -
Hirofumi TERASAWA, Masamichi SUGIMORI, Akio EJIMA, Hiroaki TAGAWA1989 Volume 37 Issue 12 Pages 3382-3385
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSAs part of our attempts to employ the unnatural (R)-type compound (8), which was produced by optical resolution of the pyranoindolizine 6, in the synthesis of natural (20S)-camptothecin, inversion of the configuration at the tertiary alcohol of the (4R)-pyranoindolizine 11 to give the (4S)-isomer 14 was achieved in 33% yield via the methanesulfonate 12.View full abstractDownload PDF (633K) -
Masahiro KAJIWARA, Katsuyuki KURUMAYA, Yoshiyuki KOHNO, Kenichi TOMITA ...1989 Volume 37 Issue 12 Pages 3386-3389
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe oxidation of tyrosine by monophenol monooxygenase (tyrosinase : EC 1.10.3.1) to melanin has been studied by a combination of ultraviolet, circular dichroism, and nuclear magnetic resonance techniques. It is demonstrated that the chiral intermediate (dopachrome) is generated stereoselectively in this enzymic reaction.View full abstractDownload PDF (517K) -
Kimiaki ISOBE, Naoko TAKEDA, Kunihiko MOHRI, Yoshisuke TSUDA1989 Volume 37 Issue 12 Pages 3390-3392
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSThe oxidation of methoxy-isochromans and -isochromanones with ceric ammonium nitrate in methanol introduced a new methoxy group regioselectively at a benzylic position para to the methoxy function on the aromatic nucleus.View full abstractDownload PDF (471K) -
Takashi MICHIDA, Hiromi HATSUMURA, Hiroteru SAYO1989 Volume 37 Issue 12 Pages 3393-3395
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSTwo-electron anodic oxidation of o-nitrophenylthioiminocyclopentane (1) in methanol, followed by nucleophilic attacks of solvent and water (the latter present as an impurity in the solvent), gave methyl sulfinate and cyclopentaneimine. On the other hand, one-electron oxidation of o-nitrophenylthioiminocycloalkanes (1-6) in acetonitrile followed by deprotonation of the cation radical (B) gave the neutral radical (C), whcih then gave the thiyl radical (E). The rest of C reacted with E to give N, 2-bis(o-nitrophenylthio)iminocycloalkanes, whose oxidation gave the final products (9-14). The results of cyclic voltammetry of 1-6 also show that the initial steps of anodic oxidation of 1-6 in acetonitrile and in methanol are one- and two-electron oxidations, respectively.View full abstractDownload PDF (498K) -
Hiroyuki ISHIBASHI, Yumiko MIKI, Yoshiaki IKEDA, Akiko KIRIYAMA, Masaz ...1989 Volume 37 Issue 12 Pages 3396-3398
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESSA series of (methylsulfinyl)acetamides 4 reacted with electron-rich arenes in the presence of p-toluenesulfonic acid to give α-(methylthio)arylacetamides 5, 6, and 7, some of which were transformed into biologically active arylethylamines such as (±)-macromerine.View full abstractDownload PDF (457K) -
Nobuo IKOTA1989 Volume 37 Issue 12 Pages 3399-3402
Published: December 25, 1989
Released on J-STAGE: March 31, 2008
JOURNAL FREE ACCESS(2R, 3S, 4S)-3, 4-Dihydroxy-2-hydroxymethylpyrrolidin (6) and polyoxamic acid (20) were synthesized from (S)-pyroglutamic acid derivatives (1 and 7). The key reactions are the selective mono-O-benzylation of 1 and 7, and subsequent Mitsunobu reaction to invert the stereochemistry of the free hydroxy group of 3 and 11.View full abstractDownload PDF (761K)