Regular Issue

Vol. 51, No. 3, 1999

22 data found. 1 - 22 listed
Communication | Regular issue | Vol 51, No. 3, 1999, pp. 471 - 474
Published online:
DOI: 10.3987/COM-98-8409
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


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.

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Communication | Regular issue | Vol 51, No. 3, 1999, pp. 475 - 479
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DOI: 10.3987/COM-98-8418
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.


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.

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Communication | Regular issue | Vol 51, No. 3, 1999, pp. 481 - 487
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DOI: 10.3987/COM-98-8423
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


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.

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Communication | Regular issue | Vol 51, No. 3, 1999, pp. 489 - 492
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DOI: 10.3987/COM-98-8427
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


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.

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Communication | Regular issue | Vol 51, No. 3, 1999, pp. 493 - 496
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DOI: 10.3987/COM-98-8429
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


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.

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Communication | Regular issue | Vol 51, No. 3, 1999, pp. 497 - 500
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DOI: 10.3987/COM-98-8430
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


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).

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Communication | Regular issue | Vol 51, No. 3, 1999, pp. 501 - 504
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DOI: 10.3987/COM-98-8434
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


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.

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Paper | Regular issue | Vol 51, No. 3, 1999, pp. 505 - 512
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DOI: 10.3987/COM-98-8368
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


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.

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Paper | Regular issue | Vol 51, No. 3, 1999, pp. 513 - 546
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DOI: 10.3987/COM-98-8385
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


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.

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Paper | Regular issue | Vol 51, No. 3, 1999, pp. 547 - 556
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DOI: 10.3987/COM-98-8395
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


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.

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Paper | Regular issue | Vol 51, No. 3, 1999, pp. 557 - 565
Published online:
DOI: 10.3987/COM-98-8402
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


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.

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Paper | Regular issue | Vol 51, No. 3, 1999, pp. 567 - 574
Published online:
DOI: 10.3987/COM-98-8416
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


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.

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Paper | Regular issue | Vol 51, No. 3, 1999, pp. 575 - 591
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DOI: 10.3987/COM-98-8417
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


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.

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Paper | Regular issue | Vol 51, No. 3, 1999, pp. 593 - 598
Published online:
DOI: 10.3987/COM-98-8421
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


(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).

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Note | Regular issue | Vol 51, No. 3, 1999, pp. 599 - 604
Published online:
DOI: 10.3987/COM-98-8350
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


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.

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Note | Regular issue | Vol 51, No. 3, 1999, pp. 605 - 609
Published online:
DOI: 10.3987/COM-98-8408
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


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.

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Note | Regular issue | Vol 51, No. 3, 1999, pp. 611 - 615
Published online:
DOI: 10.3987/COM-98-8411
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


Employing cuprous chloride as a catalyst in the Leuckart reaction between formamide and acetophenone leads to the formation of 4-phenylpyrimidine in satisfactory yield.

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Note | Regular issue | Vol 51, No. 3, 1999, pp. 617 - 625
Published online:
DOI: 10.3987/COM-98-8420
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


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.

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Note | Regular issue | Vol 51, No. 3, 1999, pp. 627 - 630
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DOI: 10.3987/COM-98-8425
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


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.

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Note | Regular issue | Vol 51, No. 3, 1999, pp. 631 - 637
Published online:
DOI: 10.3987/COM-98-8426
Acetylenic Derivatives of Thioquinolines

Stanislaw Boryczka

*Department of Organic Chemistry, The Medical University of Silesia, Jagiellonska Str. 4, 41-200 Sosnowiec, Poland


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.

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Note | Regular issue | Vol 51, No. 3, 1999, pp. 639 - 647
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DOI: 10.3987/COM-98-8438
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


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.

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Review | Regular issue | Vol 51, No. 3, 1999, pp. 649 - 670
Published online:
DOI: 10.3987/REV-98-512
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


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.

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22 data found. 1 - 22 listed