HETEROCYCLES
An International Journal for Reviews and Communications in Heterocyclic ChemistryWeb Edition ISSN: 1881-0942
Published online by The Japan Institute of Heterocyclic Chemistry
Regular Issue
Vol. 51, No. 3, 1999
Published online:
■ Unusual Ring Contraction of 3H-Pyrano[2,3-c]quinolin-5(6H)-ones to Furo[2,3-c]quinolin-4(5H)-ones
Krishna C. Majumdar,* Anup K. Kundu, and Paritosh Biswas
*Department of Chemistry, University of Kalyani, Kalyani-741 235, W. B., India
Abstract
A number of 1-aryloxymethyl-3H-pyrano[2,3-c]quinolin-5(6H)-ones (1a-h) on heating in N,N-diethylaniline for 8 h afforded 1-aryloxymethyl-2-methyl-furo[2,3-c]quinolin-4(5H)-ones (2a-h) in 66-79 % yields.
Published online:
■ 2-Cyanamidothiazoles from 3-Propynylthio-1,2,4-triazoles
Dallas K. Bates,* Mingde Xia, Margarette Aho, Hans Mueller, and Ramani R. Raghavan
*Department of Chemistry, College of Sciences and Arts, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan, 49931, U.S.A.
Abstract
3-Allylthioallyl triazoles (5) rearrange to N-allyl derivatives (6) while 3-(2-propynyl) derivatives (2) provide 4,5-disubstituted 2-cyanamidothiazoles (9) in refluxing p-xylene. At lower temperatures N-allenyl derivatives (8) may be isolated and converted independently to 9. Intermediate allenes exhibit sigmatropic inversion of substituents characteristic of Claisen rearrangement.
Published online:
■ New Syntheses of 4(5)-Aryl-5(4)-(2-chromonyl)-1,2,3-triazoles from 2-Styrylchromones and Sodium Azide
Artur M. S. Silva,* Judite S. Vieira, José A. S. Cavaleiro, Tamás Patonay, Albert Lévai, and José Elguero
*Department of Chemistry, Universit y of Aveiro, 3810 Aveiro, Portugal
Abstract
The reactions of 2-α-bromostyrylchromones or 2-styrylchromones with sodium azide afforded 4(5)-aryl-5(4)-(2-chromonyl)-1,2,3-triazoles. In the case of 2-α-bromostyrylchromones, the unexpected 1-aryl-5-(2-chromonylmethyl)tetrazoles have been obtained as minor products and the mechanism of its formation is discussed. The bromination/dehydrobromination reactions of 2-styrylchromones were also studied.
Published online:
■ Radical Cyclizations of Vinylogous Systems Involving Oxime Ethers Connected with Carbonyl Groups
Takeaki Naito,* Daisuke Fukumoto, Kumiko Takebayashi, and Toshiko Kiguchi
*Kobe Pharmaceutical University, Motoyamakita, Higashinada, Kobe 658-8558, Japan
Abstract
Stannyl radical addition-cyclization of the isolated oximeethers or α,β-unsaturated oxime ethers connected by a tether to α,β -unsaturated aldehydes or ketones provides a new entry to the adjacently functionalized heterocycles.
Published online:
■ Et2AlCl Promoted Coupling Reactions of 4-Hydroxy-2-pyrone or 4-Hydroxycoumarine with Aldehydes: Synthesis of Methylenebis-(4-hydroxy-2-pyrone) or Methylenebis-(4-hydroxycoumarine) Derivatives
Hisahiro Hagiwara,* Shigeki Miya, Toshio Suzuki, Masayoshi Ando, Isao Yamamoto, and Michiharu Kato
*Graduate School of Science and Technology, Nigata University, 8050, 2 no-cho, Ikarashi, Nigata 950-2181, Japan
Abstract
Methylenebis(4-hydroxy-2-pyrone) or methylenebis(4-hydroxy-coumarin) derivatives (5) have been synthesized from 4-hydroxy-2-pyrones (6) and (8) or 4-hydroxycoumarine (10) with aldehydes (4) in the presence of diethylaluminum chloride.
Published online:
■ Tandem Nucleophilic Reaction Leading to Hydrofurans: Application to One-Pot Synthesis of Antitumor Naphthofuran Natural Product
Hisahiro Hagiwara,* Kouji Sato, Toshio Suzuki, and Masayoshi Ando
*Graduate School of Science and Technology, Nigata University, 8050, 2 no-cho, Ikarashi, Nigata 950-2181, Japan
Abstract
The reaction of enolates of 1,3-dicarbonyl compounds (1) with 3,4-dibromo-2-butanone (2) afforded hydrofuran derivatives (4) or (5) in the presence of DBU in THF and the reaction was applied to the one-pot synthesis of antitumor naphthofuran natural products (29).
Published online:
■ Model Studies on Interconversion of Roxburghine-Type Alkaloids. Acid-catalysed Epimerization of C-12b Substituted Indolo[2,3-a]quinolizidine Derivatives
Mauri Lounasmaa,* Mathias Berner, Anders Månsus, and Arto Tolvanen
*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, P.O. Box 6100, FIN-02150 Espoo, Finland
Abstract
C-12b Methyl substituted indolo[2,3-a]quinolizidines possessing different structural features were prepared as model compounds to investigate whether different roxburghine alkaloids can be obtained by acid-catalysed epimerization. When they were subjected to epimerization under strongly acidic conditions (TFA), indoloquinolizidines (7) and (8) and lactams (12) and (13) epimerized as expected but the vinylogous urethanes (4) and (5) remained unaffected. The results indicate that the mechanism starting with protonation at the β-position of indole (Mechanism 1) is active in the acid-catalysed epimerization of vinylogous urethanes. This further suggests that roxburghine alkaloids do not epimerize at C-19.
Published online:
■ Synthesis and Structural Characterization of Enantiopure Camphor-based Di-, Tri- and Tetrasulfides
Stephan Otten, Roland Fröhlich, and Günter Haufe*
*Organisch-Chemisches Institut, Westfälische Wihelms-Universität Münster, Corrensstrasse 40, D-48149 Münster, Germany
Abstract
The dithiane (6) was synthesized by bromine oxidation of the dithiol (5), despite the significant steric strain in the pentacyclic system. In the presence of elemental sulfur the oxidation of 5 gave selectively the 1,2,3-trithiacycloheptane (7), while from the diastereomeric dithiol (4) under the same conditions the 1,2,3,4-tetrathiacyclooctane (8) was obtained in good yield. The geometry of the molecules was determined by X-Ray analysis.
Published online:
■ Syntheses of Phosphonato-substituted Azolo[1,2,4]triazines with Potential Biomedical Applications
Thomas Ankenbrand and Richard Neidlein*
*Pharmazeutisch-Chemishces Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany
Abstract
The syntheses of [1,2,4]triazino[4,3-b][1,2,4]indazol-3-yl-phosphonic acid dialkyl esters (5-7), pyrazolo[3,2-c][1,2,4]triazin-3-yl-phosphonic acid dialkyl esters (9-11) and [1,2,4]triazolo[3,2-c][1,2,4]triazin-3-ylphosphonic acid dialkyl esters (13-15) are desribed. The treatment of 7-methylpyrazolo[1,2,4]triazin derivatives (9c,d, 11c-e) with N-bromo- or N-iodosuccinimide yields the corresponding 8-halogen compounds (19a-h). The 8-iodo derivatives could be coupled with phenylacetylene.
Published online:
■ Reaction of Cyclohexa-1,2,3-triene with N,α-Diphenylnitrone: Formation of Seven-membered Cyclic Amines via Piradone Derivatives
Michihito Sakura, Shinichi Ando, Atsushi Hattori, and Katsuhiro Saito*
*Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
Abstract
Cyclohexa-1,2,3-triene was generated in the presence of N,α-diphenylnitrones to form seven-membered cyclic amines via piradone derivatives, which were formed through [4+2] type cycloaddition of the central double bond of cyclohexa-1,2,3-triene with nitrones.
Published online:
■ Competition between C- and O-Alkylation Reactions in 5-Nitroimidazole Series: Influence of Nucleophile
Kamel Benakli, Mustapha Kaafarani, Michel P. Crozet, and Patrice Vanelle*
*Laboratoire de Chimie Organique, Faculté de Pharmacie, Université de la Méditerranée, 27, Boulevard Jean Moulin, 13385 Marseille Cedex 05, France
Abstract
The new reductive alkylating agent, 2-(4-chloromethylstyryl)-1-methyl-5-nitro-1H-imidazole gives exclusively O-alkylation with 2-nitropropane anion. The electron-transfer C-alkylation is observed with the anions of ethyl 2-nitro-propionate and dialkyl α-substituted malonates. The competition between C- and O-alkylation reactions depends on the nature of the nucleophile because of the low rate of decomposition of the radical anion of the alkylating agent.
Published online:
■ A Nitro Group Distorting 2-Quinolone Skeleton
Nagatoshi Nishiwaki, Chitose Tanaka, Motoki Asahara, Noriko Asaka, Yasuo Tohda, and Masahiro Ariga*
*Department of Chemistry, Osaka Kyoiku University, 4-698-1 Asahigaoka, Kashiwara, Osaka 582-8582, Japan
Abstract
1-Methyl-3,6,8-trinitro-2-quinolone shows high reactivity compared with 1-methyl-3,6-dinitro-2-quinolone. It was found the 8-nitro group activates a 2-quinolone ring sterically rather than electronically.
Published online:
■ Simple Route to Azabicyclic Peroxides from Tetramic Acid Derivatives Using Manganese(III)-based Molecular Oxygen Trapping Reaction
Firoz Alam Chowdhury, Hiroshi Nishino,* and Kazu Kurosawa
*Department of Chemistry, Faculty of Science, Kumamoto University, Kurokami 2-39-1, Kumamoto 860-8555, Japan
Abstract
A simple one-step synthesis of azabicyclic peroxides was achieved by the manganese(III)-mediated oxidative formal [2+2+2] cycloaddition. The reaction of alkenes (1) with pyrrolidinediones (2) was carried out with manganese(III) acetate in acetic acid at 23 °C under a dry air stream to give 1-hydroxy-8-aza-2,3-dioxabicyclo[4.3.0]nonan-7-ones (3) in good to quantitative yields. Similar reactions at elevated temperature gave 3-ethyl-2,4-pyrrolidinediones (4) and/or 3-ethenyl-2,4-pyrrolidinediones (5) in good yields.
Published online:
■ Chemoenzymatic Enantioselective Synthesis of (-)-Indolizidine 167B
Robert Chênevert,* Ghodsi Mohammadi Ziarani, and Mohammed Dasser
*Département de Chimie, Faculté des Sciences et de Génie, Université Laval, Cité Universitaire, Québec, G1K 7P4, Canada
Abstract
(5R, 9R)-(-)-Indolizidine 167 B was synthesized in 8 steps from N-benzyloxycarbonyl-cis-2(R)-acetoxyrnethy1-6(S)-hydroxymethy1piperidine (2) in an overall yield of 60%. This starting material was obtained from enzymatic desymmetrization of the corresponding meso diacetate (1).
Published online:
■ The Preparation and Lead Tetraacetate Oxidation of Mixed Bisaroyl Hydrazones of Biacetyl to 1-(α-Aroyloxyarylideneamino)-3,5-dimethyl-1,2,3-triazoles
Constantina P. Hadjiantoniou-Maroulis
*Department of Chemistry, Laboratory of Organic Chemistry, Aristotle University of Thessaloniki, P.O.B. 103, GR-540 06 Thessaloniki, Greece
Abstract
The preparation and lead tetraacetate oxidation of the mixed aroyl hydrazones of biacetyl (2) to the pairs of isomeric 1-(α-aroyloxy-arylideneamino)-3,5-dimethyl-1,2,3-triazoles (6) and (6’) is described. The product ratio of 6/6’ is evaluated in terms of the stability imparted to the zwiterionic intermediate (5) by the different substituents on the aroyl groups.
Published online:
■ A New trans-Clerodane Diterpene Lactone from Conyza blinii
Liping Xu, Dean Guo,* Jianshen Liu, Junhua Zheng, Kazuo Koike, Zhonghua Jia, and Tamotsu Nikaido*
*Department of Pharmacognosy, School of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan
Abstract
A new trans-clerodane lactone, conyzalactone, together with six known compounds, was isolated from the aerial parts of composite Conyza blinii. Its structure was elucidated on the basis of extensive NMR analysis and X Ray crystallographic data.
Published online:
■ Synthesis of 4-Phenylpyrimidine from Acetophenone and Formamide
Irene Helland and Tore Lejon*
*Departmentof Chemistry, Faculty of Science, University of Tromso, N-9037 Tromso, Norway
Abstract
Employing cuprous chloride as a catalyst in the Leuckart reaction between formamide and acetophenone leads to the formation of 4-phenylpyrimidine in satisfactory yield.
Published online:
■ Pyridazines, 88. On the Attack of S-Nucleophiles at 3,6-Disubstituted N-Methyl-N-phenylpyridazine-4-carboxamide
Gottfried Heinisch, Barbara Matuszczak,* Kurt Mereiter, and Jens C. Wilke
*Institut für Organische und Pharmazeutisch Chemie, Universität Innsbruck, Innrain 52, A-6020 Innsbruck , Austria
Abstract
Reactions of 3,6-dichloro-N-methyl-N-phenylpyridazine-4-carboxamide with S-nucleophiles (2-amino-thiophenol, benzyl mercaptan) were studied, structural elucidation of the reaction products was achieved by means of X-Ray analysis and NMR experiments (NOE difference spectroscopy), respectively.
Published online:
■ A Convenient and Facile Synthesis of 3-Trifluoromethyl-1,2,5-oxadiazoles with the Use of Silica Gel as an Effective Catalyst
Yasuhiro Kamitori*
*Department of Chemical Science andd Engineerring, Faculty of Engineering, Kobe University, Kobe 657-8501, Japan
Abstract
Silica gel catalyzed intramolecular dehydration of 1,1,1-trifluoro-alkane-2,3-dione dioximes (2) afforded 3-trifluoromethyl-1,2,5-oxadiazoles (3) in satisfactory yields.
Published online:
■ Acetylenic Derivatives of Thioquinolines
Stanislaw Boryczka
*Department of Organic Chemistry, The Medical University of Silesia, Jagiellonska Str. 4, 41-200 Sosnowiec, Poland
Abstract
Various 3,4-substituted quinoline sulfides possessing a propargylthio and/or propargyloxy groups at the 3- and 4- positions were prepared by the reaction of thioquinanthrene with alkoxides.
Published online:
■ Diastereoselectivity in the Methylation and Reduction of 3-Aryl-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazol-4-ones
Hyoung Rae Kim,* Hyun Ju Park, Seung Il Shin, Byung Hee Lee, Jae Nyoung Kim, and Eung K. Ryu
*Bioorganic Science Division, Korea Research Institute of Chemical Technology, P.O. Box 107, Yousung, Taejeon, 305-600, Korea
Abstract
Various 3-aryl-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazol-4-ones were methylated at 3a-positions and reduced by NaBH4 to afford the corresponding 3a,4-cis-3a,7a-cis-3a-methyl-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazo1-4-ols with excellent diastereoselectivity. The resulting hexahydro-1,2-benzisoxazol-4-ols were easily converted to the corresponding 2-aroyl-2-rnethylcyclohexane-1,3-diols by catalytic hydrogenation with Raney Ni.
Published online:
■ Conformational Study of Geissoschizine Isomers and Their Model Compounds
Mauri Lounasmaa* and Pirjo Hanhinen
*Laboratory for Organic and Bioorganic Chemistry, Technical University of Helsinki, P.O. Box 6100, HUT-02150 Espoo, Finland
Abstract
Study was made of the major factors affecting the conformational equilibrium between the C and D rings of geissoschizine isomers (1-4) and several of their model compounds (5-24). Conclusions are mainly based on 13C NMR data.