HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Special Issue
Sho Ito's Special Issues, Vol. 54, No. 2, 2001
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■ Photoinduced Electron-Transfer Reactions between C60 and Cyclic Disiliranes (c-R2Si-X-SiR2; X=SiR2, CH2, O, NPh, S)
Yoshiko Sasaki, Mamoru Fujitsuka, Osamu Ito,* Yutaka Maeda, Takatsugu Wakahara, Takeshi Akasaka, Kaoru Kobayashi, Shigeru Nagase, Masahiro Kako, and Yasuhiro Nakadaira
*Institute for Chemical Reaction Science, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan
Abstract
Photoinduced electron-transfer reactions between various cyclic disiliranes (c-R2Si-X-SiR2; X = SiR2, CH2, O, NPh, and S) and photo-excited C60 in polar PhCN solvent have been investigated by 532 nm laser photolysis with the observation of the transient absorption bands in the near-IR region. The transient absorption band of the anion radical of C60 (C60•-) appeared at 1070 nm, accompanying the decay of the excited triplet state of C60 (3C60*), showing that electron transfer takes place from c-R2Si-X-SiR2 to 3C60*. The rates and quantum yields for electron transfer via 3C60* were compared with changing X. The final products in PhCN were identified as mono-adducts and bis-adducts of R2Si-X-SiR2 with PhCN, but not with C60.
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■ Synthesis of Ciguatoxin (2S,5R)-ABC Segment
Rungnapha Saeeng and Minoru Isobe*
*Laboratory of Organic Chemistry, School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan
Abstract
An (2S, 5R)-ABC segment of ciguatoxin has been synthesized based on the previous route for the opposite enantiomer by switching enantiomerism of a pseudosymmetric intermediate. This route has been improved in several steps and ended up with a vinylthioether group for future extension toward the D ring of ciguatoxin molecule
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■ 3-Aza[5]metacyclophanes: Synthesis and Reactions
Daniël S. van Es, Maurice J. van Eis, Stephen N'Krumah, Norbert Gret, Arne Egberts, Marianne de Rijke, Franciscus J. J. de Kanter, Willem H. de Wolf, Friedrich Bickelhaupt,* and Anthony L. Spek
*Scheikundig Laboratorium, Vrije Universiteit, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands
Abstract
The synthesis of the dichloro substituted 3-aza[5]metacyclophane (6b) has been achieved starting from the N-tosyl derivative (7) by a four-step procedure consisting of dichlorocarbene addition, flash vacuum thermolysis, a second dichlorocarbene addition, and base catalyzed elimination; similarly, the monochloro analogue (6c) was prepared. Their structure was confirmed by X-Ray crystal structure determination which indicated that the deformation of their benzene rings was only slightly stronger than that of the carbon analogue 8,11-dichloro[5]metacyclophane (15b). 1H NMR spectroscopy showed that in solution, like in the crystal, both 6b and 6c occurred in the exo conformation exclusively. Contrary to expectation, the reactivity of 6b and 6c towards several dienophiles was clearly higher than that of 15b. Thermally, 6b was converted to the 1,2,4,5-tetrahydropyrrolo[3,2,1-hi]indole (23b) by a remarkable intramolecular nucleophilic attack of the tosylamide nitrogen on the benzene ring.
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■ Substitution vs Addition. Regioselective Electro-bromination of Benzofuran
Hideo Tanaka,* Yusuke Kawakami, Manabu Kuroboshi, and Sigeru Torii
*Department of Applied Chemistry, Faculty of Engineering, Okayama University, Tsushima-Naka, Okayama 700-8530, Japan
Abstract
Regioselective electro-bromination of benzofuran (2) was achieved successfully by an adequate choice of solvents and bromide salts to afford 5-bromobenzofuran (1), 5,7-dibromobenzofuran (3), and 2,3-dibromo-2,3-dihydrobenzofuran (4), respectively. Upon electrolysis of benzofuran (2) in AcOH/H2O (100/1) containing NH4Br, substitution at the C(5)-position of benzofuran (2) proceeded smoothly to afford 5-bromobenzofuran (1). After passage of totally 4 F/mol of electricity in a similar medium, 5,7-dibromobenzofuran (3) was obtained as a sole product. On the other hand, electrolysis of benzofuran (2) in CH2Cl2/H2O (1/1) and/or AcOH/H2O (10/1) in the presence of either NaBr or NH4Br afforded 2,3-dibromo-2,3-dihydrobenzofuran (4), exclusively.
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■ Syntheses, Structure and Conducting Properties of Halogenated Ethylene- dioxytetrathiafulvalenes
Masahiko Iyoda,* Yoshiyuki Kuwatani, Eiji Ogura, Kenji Hara, Hironori Suzuki, Takahiro Takano, Koji Takeda, Jun-ichi Takano, Kohei Ugawa, Masato Yoshida, Haruo Matsuyama, Hiroyuki Nishikawa, Isao Ikemoto, Takehiro Kato, Naoki Yoneyama, Jun-ichi Nishijo, Akira Miyazaki, and Toshiaki Enoki
*Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
Abstract
4,5-Diiodo-, 4,5-dibromo-, and 4,5-dichloro-4',5'-ethylenedioxytetra-thiafulvalenes (EDO-TTFI2, EDO-TTFBr2, and EDO-TTFCl2) were synthesized in moderate to good yields by the two routes. The first route contains the reaction of EDO-TTF with LDA, followed by quenching with halogenated reagents, and the second route consists of the P(OR)3-mediated cross-coupling of 4,5-dihalogenated 1,3-dithiole-2-ones with 4,5-ethylenedioxy-1,3-dithiole-2-thione. The structures of EDO-TTFI2 and EDO-TTFCl2 were determined by X-Ray analysis. The radical-cation salts derived from EDO-TTFI2, EDO-TTFBr2, and EDO-TTFCl2 show high conductivities, although these compounds contain electron-withdrawing halogens as the substituent.
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■ Intramolecular Complex Formation between Flexible Molecular Tweezers and Weak Electron Acceptor
Hirotaka Kurebayashi and Yoshimasa Fukazawa*
*Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
Abstract
A flexible receptor having three aromatic chromophores can bind a weak electron acceptor which is linked covalently to the receptor with alkyl chain of an appropriate length. The receptor has tweezers type conformation when the acceptor was entrapped within the cavity. Sandwich type donnor-acceptor-acceptor arrangement was realized in solution.
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■ Short-Step Synthesis of Some Santanolides, Dehydroisoerivanin, Isoerivanin, Ludovicin C, and 1α,3α-Dihydroxyarbusculin B by the Use of the Organoselenium Reduction Method of Epoxy Ketones
Toshio Suzuki and Masaaki Miyashita*
*Division of Chemistry, Graduate School of Sceince, Hokkaido University, Sapporo 060-0810, Japan
Abstract
Short-step synthesis of four santanolides, dehydroisoerivanin (1), isoerivanin (2), ludovicin C (3), and 1α, 3α-dihydroxyarbusculin B (4) is described in which the organoselenium reduction of a cross diepoxy ketone was involved as a key step.
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■ Synthetic Studies on Halichlorine and Pinnaic Acid: Palladium-mediated Construction of the Bicyclic Spiro Core
Wakako Yokota, Mitsuru Shindo, and Kozo Shishido*
*Institute for Medicinal Resources, University of Tokushima, Sho-machi 1, Tokushima 770-8505, Japan
Abstract
Palladium-mediated cyclization of 19 and 23 directed toward the construction of the bicyclic core (3), which would serve as a key intermediate for the total synthesis of halichlorine (1) and pinnaic acid (2), was explored and found to proceed for 19 in a highly diastereoselective manner furnishing the unnatural isomer (21), and providing a mixture of the desired product (3) and (21) for 23 .
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■ Synthesis of Indeno[1,2-b]phenanthrene-Type Heterocycles by Cyclo- aromatization of Acyclic Non-conjugated Benzotetraynes
Kazuhiro Miyawaki, Fukuko Ueno, and Ikuo Ueda*
*The Institute of Scientific and Industrial Research, Osaka University, 8-1, Mihogaoka, Ibaraki, Osaka 567-0047, Japan
Abstract
A novel and simple procedure for the preparation of 6-oxa-, 6-thia-, and 6-azaindeno[1,2-b]phenanthrenes (4) by thermal cycloaromatization of acyclic non-conjugated benzotetraynes (3) is described.
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■ Chemoenzymatic Preparation of Oligoglycosides of Silybin, the Flavonolignan from Silybum marianum
J. Kubisch, P. Sedmera, P. Halada, R. Gazák, N. Skottová, V. Simánek,* and V. Kren
*Institute of Medical Chemistry, Palacky University, Hnevotínská 3, CZ-775 15 Olomouc, Czech Republic
Abstract
Starting from 23-O-β-D-glucopyranosyl silybin (2) and 23-O-β-D-galactopyranosyl silybin (3), α-oligoglucosides of silybin were synthesized employing cyclodextrin glucanotransferase from Bacillus stearothermophillus (E.C. 2.4.1.19). Oligoglycosides of silybin were tested for the LDL antioxidant activity in vitro.
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■ Synthesis of Alternariolide Analogs for Photoaffinity-Labeling
Chikanori Morita, Toshikatsu Okuno, Kimiko Hashimoto, and Haruhisa Shirahama*
*School of Science, Kwansei Gakuin University, Uegahara, Nishinomiya 662-8501, Japan
Abstract
Two photoaffinity-labeling analogs of alternariolide were synthesized. These peptides contain the 3-nitrophenyl-3-trifluoromethyldiazirine moiety for easy detection after irradiation experiment.
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■ Synthesis, Structure and Spectroscopic Characteristics of 2'-Boryl-4''-dimethylaminochalcones. Effect of an Intramolecular Boron-Oxygen Coordinate Bond to the Conjugated System
Toshihiro Murafuji,* Kenji Sugimoto, Sachiko Yanagimoto, Tomokazu Moriya, Yoshikazu Sugihara,* Yuji Mikata, Masako Kato, and Shigenobu Yano
*Department of Chemistry, Faculty of Science, Yamaguchi University, Yamaguchi 753-8512, Japan
Abstract
2’-Diethylboryl-4”-dimethylaminochalcone (1) and the related compounds (4)-(7) bearing a dioxyboryl group in the 2’-position were synthesized, and the effect of the intramolecular boron-oxygen coordinate bond on the spectroscopic characteristics of 4”-dimethylaminochalcone chromophore was examined by comparison with 4”-dimethylaminochalcone (2) using UV/VIS and fluorescence spectra.
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■ Preparation of Benzoheterocycles Containing Group 14 Elements Using Zirconacyclopentadienes
Yanzhong Li, Yasuyuki Ura, Fu-Yu Tsai, Feng Xu, and Tamotsu Takahashi*
*Catalysis Research Center and Graduate School of Pharmaceutical Sciences, Hokkaido University, and CREST, Science and Technology Corporation (JST), Sapporo 060-0811, Japan
Abstract
Benzoheterocycles containing group 14 elements such as benzosilacycles, benzogermacycles and benzostannacycles were prepared from the corresponding zirconacycles and alkynes in the presence of CuCl or NiBr2(PPh3)2. Monomers for the synthesis of benzoheterocyclic polymers containing silicon and germanium were synthesized by this method.
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■ Chemical Constituents of Two Oriental Orchids, Calanthe discolor and C. liukiuensis: Precursor Indole Glycoside of Tryptanthrin and Indirubin
Toshiyuki Murakami, Akinobu Kishi, Tetsuo Sakurama, Hisashi Matsuda, and Masayuki Yoshikawa*
*Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan
Abstract
Two indole glycosides, calanthoside and glucoindican, were isolated from two oriental orchids, Calanthe discolor LINDL. and C. liukiuensis SCHLTR., together with calaphenanthreol, calaliukiuenoside, and bioactive known alkaloids, tryptanthrin, indirubin, and isatin. The structures of calanthoside, glucoindican, calaphenanthreol, and calaliukiuenoside were determined on the basis of physicochemical and chemical evidence. Furthermore, it was found that enzymatic hydrolysis of calanthoside furnished tryptanthrin as the main product, whereas indirubin and isatin were obtained by acid hydrolysis of calanthoside
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■ Synthesis of 2,3,4,5-Tetrahydro- 1H-2-benzazepines via Pummerer- Type Cyclization of N-Arylmethyl- N-(3-phenylsulfinylpropyl)formamides
Yoshie Horiguchi, Toshiaki Saitoh, Sachiko Terakado, Konomi Honda, Tomoko Kimura, Jun Toda, and Takehiro Sano*
*Showa Pharmaceutical University, 3-3165, Higashi-tamagawagakuen, Machida, Tokyo 194-8543, Japan
Abstract
A construction of 1H-benzazepine ring system was achieved via a modified Pummerer reaction of N-arylmethyl-N-(3-phenylsulfinylpropyl)formamides (5) using trifluoroacetic acid and borontrifluoride etherate. This method provides an effective synthesis of 7,8-dimethoxy-2,3,4,5-tetrahydro-1H- 2-benzazepine (10a), the synthetic intermediate of capsazepine (1), an antagonist of capsaicin and resinferatoxin.
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■ Palladium-catalyzed Carbonylative Coupling of Hypervalent Iodonium Salts with Amidoximes: Synthesis of Oxadiazoles
Hyung-Chul Ryu, Young-Taek Hong, and Suk-Ku Kang*
*Department of Chemistry and Institute for Basic Sciences, Sungkyunkwan University, Natural Science Campus, Suwon 440-746, Korea
Abstract
Aryl-substituted oxadiazoles have been synthesized in one-pot procedure by the palladium-catalyzed carbonylative coupling of hypervalent iodonium salts with amidoximes under atmospheric pressure of carbon monoxide.
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■ Synthesis and Pharmacological Evaluation of 18,19-Dehydrobuprenorphine
Johannes Schütz, Roland Krassnig, Helmut Schmidhammer,* Klaus Wurst, Roberta Lattanzi, and Lucia Negri*
*Division of Pharmaceutical Chemistry, Institute of Pharmacy, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria
Abstract
18,19-Dehydrobuprenorphine (2) was prepared in five steps starting from thevinone (3) which is readily available from thebaine by Diels-Alder reaction. Grignard reaction with tert-BuMgBr afforded tert-butylthevinol (4) which was N-demethylated via N-cyano-tert-butylthevinol (5) using BrCN. Alkali treatment gave N-nor-tert-butylthevinol (6) which was alkylated with cyclopropylmethyl bromide to give N-cyclopropylmethyl-tert-butylthevinol (7), followed by ether cleavage with thiolate to yield 2. 18,19-Dehydrobuprenorphine displayed in opioid receptor binding studies very high affinity for μ receptors, while the affinity for κ and δ receptors was lower. In the tail-flick test in mice, compound 2 was 25 times more potent than morphine and ca. 2.5 times as potent as buprenorphine.
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■ Two Taxoids from Taxus cuspidata as Modulators of Multidrag Resistant Tumor Cells
Jun-ichi Sakai, Hirofumi Sasaki, Katsuhiko Kosugi, Shujun Zhang, Naonori Hirata, Katutoshi Hirose, Akihiro Tomida, Takashi Tsuruo, and Masayoshi Ando*
*Department of Applied Chemistry, Faculty of Engineering, Niigata University, Ikarashi 2-8050, Niigata 950-2181, Japan
Abstract
Two new taxoids taxinine NN-3 (1) (9-deacetyl taxinine) and taxinine NN-4 (2) (taxinine 11,12-epoxide) isolated from Taxus cuspidata showed high activity as modulators of multidrug-resistant tumor cells.
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■ 4-Acylhydrazinomethylene-2-phenyloxazol-5(4H)-ones as Acylating Agents: Synthesis of Salicylanilides and 1,2,4- Triazolo[4,3-b]pyridazines
Franc Pozgan, Slovenko Polanc, and Marijan Kočevar*
*Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, SI-1000 Ljubljana, Slovenia
Abstract
A simple and general method for the acylation of an amino or hydrazino group by the application of hydrazides has been developed. It starts from hydrazides (2), which are converted with 4-ethoxymethylene-2-phenyloxazol-5(4H)-one (1) to the corresponding 4-acylhydrazinomethylene-2-phenyloxazol-5(4H)-ones (3). The latter react with nitrogen-containing nucleophiles in 1,4-dioxane in the presence of triethylamine or zirconium(IV) chloride to give the corresponding amides (7) or mixtures of hydrazides (12) and 1,2,4-triazolo[4,3-b]pyridazines (11). Upon prolonged heating, compounds (11) are the main products.
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■ 5-endo-trig Radical Cyclization of N-Benzyl-2-halo-N-(6-oxo-1-cyclohexen-1-yl)acetamides
Serry A. A. El Bialy, Shinji Ohtani, Tatsunori Sato, and Masazumi Ikeda*
*Kyoto Pharmaceutical University, Misasagi, Yamashina, Kyoto 607-8414, Japan
Abstract
N-Benzyl-2-halo-N-(6-oxo-1-cyclohexen-1-yl)acetamides, upon treatment with Bu3SnH in the presence of AIBN in boiling toluene, undergo 5-endo-trig radical cyclization to give (3aR*,7aR*)-N-benzyloctahydro-7a-hydroxyindole-2,7-dione in addition to cis-N-benzyloctahydroindole-2,7-dione.
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■ Photosubstitution Reaction of Cyanoaromatics with Aliphatic Amides
Moriya Tsuji, Kimio Higashiyama, Takayasu Yamauchi, Hajime Kubo, and Shigeru Ohmiya*
*Institute of Medicinal Chemistry, Hoshi University, Ebara 2-4-41, Shinagawa-ku, Tokyo 142-8501, Japan
Abstract
Photoreaction of p- (4) and o-dicyanobenzene (6) and 4-cyanopyridine (7) with formamides (1 and 3) and 1-alkyl-2-pyrrolidone (2) produced α-aryl amides (10, 12, 13, 16, and 17). This reaction is attributable to a substitution of the carbon adjacent to the nitrogen of the amide for the cyano group in 4 and 7.
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■ Formation of Trisubstituted γ-Butyrolactones by Novel Ring Transformation of 2-Isoxazoline-2-oxides
Kazuho Harada, Kuniaki Sasaki, Keita Kumazawa, Seiko Hirotani, and Eisuke Kaji*
*School of Pharmaceutical Sciences, Kitasato University, Shirokane 5-9-1, Minato-ku, Tokyo 108-8641, Japan
Abstract
2-Isoxazoline-2-oxides (1) reacted with excess TiCl4 to yield trisubstituted γ-butyrolactones (2). The results of the structural determination by single crystal X-Ray analysis and a possible mechanism for this reaction are reported.
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■ Haterumaimides A-E, Five New Dichlorolissoclimide-Type Diterpenoids from an Ascidian, Lissoclinum Sp.
Md. Jasim Uddin, Susumu Kokubo, Kiyotake Suenaga, Katsuhiro Ueda, and Daisuke Uemura*
*Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan
Abstract
Five new dichlorolissoclimide-type diterpenoids, haterumaimides A-E, were isolated from an ascidian, Lissoclinum sp., and the absolute stereostructures of haterumaimides A-D and the relative stereostructure of haterumaimide E were determined by spectroscopic and chemical analyses. Haterumaimides A-E inhibited the first cleavage of fertilized sea urchin eggs and exhibited cytotoxicity against P388 cells.
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■ Synthesis of a Macroheterocyclic Compound through Photodecarboxylation of Potassium ω-Phthalimidoalkynoate
Dong Jin Yoo, Eun Young Kim, Michael Oelgemöller, and Sang Chul Shim*
*Department of Chemistry, School of Molecular Science-BK21 and Center for Molecular Design and Synthesis, Korea Advanced Institute of Science and Technology, 373-1 Kusong-Dong, Yusung-Gu, Taejon 305-701, Korea
Abstract
A macroheterocyclic alkyne compound is prepared through photodecarboxylation of ω-phthalimidoalkynoates in moderate yield.
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■ Sesquiterpene Lactones and Acetogenin Lactones from the Hepaticae and Chemosystematics of the Liverworts Frullania, Plagiochila and Porella
Yoshinori Asakawa,* Masao Toyota, Fumihiro Nagashima, Toshihiro Hashimoto, and Lahlou El Hassane
*Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770-8514, Japan
Abstract
Liverworts (Hepaticae) contain various sesquiterpene lactones and acetogenin lactones which show occasionally interesting biological activity and are of very valuable for the chemosystematic study of liverworts. The distribution of the sesquiterpene lactones and acetogenin lactones in liverworts and their biological activity and chemosystematics of the Frullania, Plagochila and Porella are reviewed.
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■ Cycloadditions of α,β-Unsaturated N,N-Dimethylhydrazones. A Diels- Alder Strategy for the Building of Aza-Hetero Rings
Félix Pautet, Pascal Nebois, Zouhair Bouaziz, and Houda Fillion*
*Laboratoire de Chimie Organique, Institut des Sciences Pharmaceutiques et Biologiques, Université Claude Bernard, Lyon I, 8 avenue Rockfeller, 69373 Lyon Cedex 08, France
Abstract
The reactivity and the synthetic usefulness of α,β-unsaturated N,N-dimethylhydrazones in hetero Diels-Alder reactions are reviewed. Factors influencing the regiochemistry are discussed.
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■ Quinoline Alkaloids of Orixa japonica
Shinji Funayama,* Kiyoshi Murata, and Toshiro Noshita
*Department of Bioscience and Biotechnology, Aomori University, 2-3-1 Kohbata, Aomori 030-0943, Japan
Abstract
Research works on the isolation, classification, biosynthesis, and biological activities of quinoline alkaloids from Orixa japonica (Rutaceae), done mainly by these authors, are reviewed.