Special Issue

Rolf Huisgen's Special Issues, Vol. 40, No. 2, 1995

51 data found. 31 - 51 listedFirst Previous
Paper | Special issue | Vol 40, No. 2, 1995, pp. 809 - 816
Published online:
DOI: 10.3987/COM-94-S71
Electrophilic Reaction of Pyridine, Quinoline, Isoquinoline, Their N-Oxides and Their Boron Trifluoride Complexes through Base-induced Deprotonation

Yoshinobu Tagawa, Kazuya Hama, Yoshinobu Goto, and Masatomo Hamana

*Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan

Abstract

The comparative studies have been carried out on reactivities of pyridine, quinoline, isoquinoline, and their BF3 complexes, their N-oxides, and their N-oxide-BF3 complexes, towards the electrophilic reaction through α-deprotonation.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 817 - 830
Published online:
DOI: 10.3987/COM-94-S72
Intramolecular Ene Reactions vs Competitive Pericyclic Processes: The Effect of Solvents and Salts on the Reaction of 5-Bromo-2-(3-methyl-2-butenyloxy)benzylidenemalonic Acid Dimethyl Ester

Giovanni Desimoni, Giuseppe Faita, Pier Paolo Righetti, and Francesca Vietti

*Dipartiment di Chimica Organica, Università di Pavia, V.le Taramelli 10, 27100 Pavia, Italy

Abstract

The reactivity of 5-bromo-2-(3-methyl-2-butenyloxy)benzylidenemalonic acid dimethyl ester (3) was studied in several reaction media. In aprotic solvents intramolecular ene reaction (IER) occurred to give cis and trans chroman derivatives (4) and (5), and some kinetic determinations were performed. In protic solvents, besides IER adducts, the products of intramolecular hetero-Diels-Alder reaction and Claisen rearrangement (10 and 12 respectively) were obtained. In strong protic media, deallylation occurs to give the chromen-2-one derivative (6). Finally, the reaction was investigated in acetonic solutions of inorganic perchlorate (barium, lithium, magnesium, and sodium), and these conditions enhanced chemo- and stereo-selectivity and increased the rate. The kinetic effect was dramatic for magnesium perchlorate.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 831 - 836
Published online:
DOI: 10.3987/COM-94-S76
A Synthesis of a New Type Heterocyclic Compound by [2+2]Cycloaddition of Isoquinuclidine Having an Enamine Moiety

Hiroshi Hongo, Hiroto Nakano, and Yuko Okuyama

*Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan

Abstract

Thermal [2+2] cycloaddition of isoquinuclidine having an enamine moiety with acetylenes regio- and stereo-selectively gave a new type of heterocyclic ring system, 7-azatricyclo[4.2.2.02,5]decanes.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 837 - 840
Published online:
DOI: 10.3987/COM-94-S78
Synthesis, Spectral Characterization and Fluorescence Properties of O-Methyl-S-alkyl-N-(9-acridinyl)iminothiocarbonates

Pavol Kristian, Juraj Bernát, Dana Mazagová, and Marián Antalík

*Department of Organic Chemistry, P. J. Safárik University, Moyzesova 11, SK-04154 Kosice, Slovakia

Abstract

A simple method for preparation of O-methyl-S-alkyl-N-(9-acridinyl)iminothiocarbonates via addition of sodium methoxide to 9-isothiocyanatoacridines (1a-1d) and subsequent alkylation of formed sodium salts (2a-2d) with methyl iodide and butyl bromide has been elaborated.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 841 - 849
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DOI: 10.3987/COM-94-S80
1H-Imidazole Preparation via Permanganate Dehydrogenation of 2-Imidazolines

Ma. Elena Campos, Rogelio Jiménez, Flor Martínez, and Héctor Salgado

*Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, I. P. N., Prol. Carpio y Plan de Ayala S/N,11340, Mexico, D.F.

Abstract

Permanganate and manganate ions were evaluated as dehydrogenating agents in the conversion of 2-substituted 2-imidazolines into the corresponding 2-substituted imidazoles. It was found that permanganate ion [Mn(VII)] in dry dioxane efficiently performs this transformation rendering this method competitive with related procedures.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 851 - 866
Published online:
DOI: 10.3987/COM-94-S86
N-[Bis(methylthio)methylene]amino Ester (BMMA): Novel Reagents for Annelation of Pyrimidine Moieties

Fritz Sauter, Johannes Fröhlich, Krain Blasl, and Karl Gewald

*Institute of Organic Chemistry, Vienna University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria

Abstract

New reagents for heterocyclic annelations containing a N-[bis(methylthio)methylene]amino moiety (=BMMA) were developed and studied regarding their scope and limitations: one-pot reaction with (hetero)aromatic ortho-aminocarbonyl-type model compounds (“carbonyl” = COOEt, COMe and CN) to a series of new benzo- or thieno-condensed pyrimidines, pyrrolo[1,2-c]pyrimidines, imidazo[1,2-c]pyrimidines and 1,2,4-triazolo[1,5-c]pyrimidines, depending on the reagent used [(MeS)2C=N-R with R = CH2-COOEt, CH2CH2COOEt, NH-COOEt].

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 867 - 903
Published online:
DOI: 10.3987/COM-94-S88
The Highly Efficient Oxidation of Olefins, Alcohols, Sulfides and Alkanes with Heteroaromatic N-Oxides Catalyzed by Ruthenium Porphyrins

Hiro Ohtake, Tsunehiko Higuchi, and Masaaki Hirobe

*Faculty of Pharmaceutical Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan

Abstract

The oxygen atom transfer reactions from 2,6-disubstituted pyridine N-oxides to olefins, allyl or benzyl alcohols and sulfides were efficiently catalyzed by ruthenium porphyrins, and these substrates were converted into epoxides, aldehydes and sulfoxides, respectively, with high selectivity. These oxidations also proceeded using other heteroaromatic N-oxides, such as pyrazine N-oxides, as oxidants. The catalytic activity of ruthenium porphyrin complexes was enhanced by the addition of a small amount of HCI or HBr. In the presence of these acids, the oxidations of alkanes or aliphatic alcohols with 2,6-dichloropyridine N-oxides were also efficiently catalyzed by ruthenium porphyrin complexes, and alcohols or ketones were afforded as oxidation products with high selectivity. In the hydroxylation of adamantane, ruthenium porphyrins work very efficiently as catalysts, giving a turnover number of up to 120000. This system offers practical advantages, such as mild conditions, tractability of oxidants and easy overall procedures. In the case of the reactions with HCI or HBr, one possibility in the reaction mechanism is that the activity of ruthenium porphyrins is enhanced in part by the coordination of CI- or Br- as axial ligands.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 905 - 911
Published online:
DOI: 10.3987/COM-94-S90
A Facile and Convenient Synthetic Method for Fluorine-containing 1,2-Dihydrobenzo[h]quinazolines and Benzo[h]quinazolines

Etsuji Okada, Ryoichi Masuda, Masaru Hojo, Hiroshi Tone, Nobuhiro Gotoh, and Ting-Kai Huang

*Department of Industrial Chemistry, Faculty of Engineering, Kobe University, Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan

Abstract

2,4-Bis(trifluoroacetyl)-1-naphthylamine (1) reacted easily with various aldehydes in the presence of aqueous ammonia under mild conditions to afford 6-trifluoroacetyl-4-trifluoromethyl-1,2-dihydrobenzo[h]quinazolines (2) in excellent yields. Dehydrogenation of 2 with DDQ gave the corresponding benzo[h]quinazolines (3) in high yields.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 913 - 924
Published online:
DOI: 10.3987/COM-94-S91
Synthesis and Properties of Diisopropylteraazabis(tropocoronand)s and Related Podands

Kimio Shindo, Luo-Cheng Zhang, Hidetsugu Wakabayashi, Hirosi Miyamae, Sumio Ishikawa, and Tetsuo Nozoe

*Department of Chemistry, Faculty of Science, Josai University, 1-1 Keyakidai, Sakado, Saitama 350-0295, Japan

Abstract

The reaction of 8-isopropylbenzo[b]cyclohept[e][1,4]oxazine (3b) with a 1.2 equivalent of α,ω-alkanediamines (2, n=3-12) afforded diisopropyltropocoronands (4, n,n’=3-12) in a one-pot procedure, while the reaction of 3b with an excess of 2 mainly gave isopropyltropopodands (8)(n,n’=4-6). The reactions of 3b with ω-aminoalcohol afforded the corresponding dihydroxy podands 11. A single-crystal X-ray diffraction analysis of the nickel (II)-complex (12b) obtained from 4 (n,n’=5) was made.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 925 - 937
Published online:
DOI: 10.3987/COM-94-S93
Studies towards Alkylthiophene-2-carboxaldehydes. Reduction of 3-Alkenylthiophenes with Triethylsilane/Trifluoroacetic Acid. Regioselectivity in Formylation Reactions of 3-Alkylthiophenes

Michael R. Detty and David S. Hays

*Office Imaging Research and Technical Development, Kodak Imaging Group, Eastman Kodak Company, Rochester New York 14650-2129, U.S.A.

Abstract

Reduction of 2- or 3-alkenylthiophenes with Et3SiH/CF3CO2H in CH2Cl2 gives the corresponding 2- or 3-alkylthiophene in >90% isolated yield. The regioselectivity of various Vilsmeier formylations of 3-alkylthiophenes was found to be a function of increasing steric bulk in the 3-alkyl substituent and in the Vilsmeier reagent . The regioselectivity of formylations of 3-alkylthiophenes by initial lithiation with butyllithium in ether followed by quenching with DMF is independent of the presence or absence of TMEDA.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 939 - 952
Published online:
DOI: 10.3987/COM-94-S94
A Novel Pathway to Alkenyl (trifluoromethanesulfonates). Application to the Conversion of Sugar Lactones into Versatile Chirons

Ivars Kalwinsh, Karl-Heinz Metten, and Reinhard Brückner

*Institut fur Organische Chemie, Georg-August-Universitat, Tammannstr. 2 D-37077 Gottingen, Germany

Abstract

Treatment of sugar-γ-lactone monoacetonides with triflic anhydride and pyridine provided monotriflates (18, ent-18, 33, and ent-33) or led to alkenyl triflates (17, ent-17, 32, and ent-32) depending on the stoichiometry. One-step conversions of these triflates into various enantiopure chirons are described.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 953 - 965
Published online:
DOI: 10.3987/COM-94-S96
Sanggenons R, S, and T, Three New Isoprentylated Phenoles from the Chinese Crude Drug "Sang-Bai-Pi" (Morus Root Bark)

Yoshio Hano, Kohichi Ichikawa, Michiko Okuyama, Juntaro Yamanaka, Tomoko Miyoshi, and Taro Nomura

*Faculty of Pharmaceutical Sciences, Toho University, 2-2-1, Miyama, Funabashi, Chiba 274-8510, Japan

Abstract

Three new isoprenylated phenols, sanggenons R(1), S(2), and T(3), were isolated from the Chinese crude drug “Sang-Bai-Pi” (Japanese name “Soha- kuhi”), the root bark of Morus sp. (Moraceae). The structures of sanggenons R, S, and T were shown to be 1, 2, and 3, respectively, on the basis of spectral evidence. Sanggenons R(1), S(2), and T(3) are regarded biogenetically as variation of Diels-Alder type adducts between chalcone derivatives and dehydroisoprenylated compounds.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 967 - 974
Published online:
DOI: 10.3987/COM-94-S97
Enzymatic Synthesis of (1R,2S)- and (1S,2R)-2-Methyl-2,3-epoxy-1-phenylpropanols

Mitsuhiro Takeshita, Reiko Yaguchi, and Yukiko Unuma

*Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan

Abstract

(1R, 2S)- and (1S, 2R)-2-methyl-2,3-epoxy-1-phenylpropanols were prepared from α-methylcinnamyl chloride by use of baker’s yeast and lipase PS.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 975 - 982
Published online:
DOI: 10.3987/COM-94-S98
Reaction of 2-Silateralins with Alkyl Halides and Ketones under Basic Conditions

Osamu Hoshino, Toru Taguchi, Kenji Miyauchi, and Atsuhiro Tatsuno

*Faculty of Pharmaceutical Sciences, Science University of Tokyo, 12, Ichigaya Funagawara-machi, Shinjuku-ku, Tokyo 162-0826, Japan

Abstract

The reaction of 2-silatetralins with alkyl halides (methyl iodide, benzyl chloride) and ketones (acetone, cyclohexanone) in sec-butyllithium (BuLi)-, sec-BuLi-tetramethylenediamine- or sec-BuLi-hexamethylphosphoramide-tetrahydrofuran media at lower temperature is described. The reaction gave rise to 1-alkylated 2-silatetralins in fair to good yield, serving a method for synthesis of a potent intermediate leading to novel silicon-containing compounds.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 983 - 991
Published online:
DOI: 10.3987/COM-94-S99
Synthesis of 5,7,8,9,10,11-Hexahydro-7-oxo-8,11-iminoazepino[1,2-b]isoquinolines

David A. Peters, Nicholas D. Yates, David I. C. Scopes, and John A. Joule

*Department of Chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, U.K.

Abstract

Methyl 4-methylene-2-oxo-3,8-diazabicyclo[3.2.1]octane-6-exo-6-carboxylates have been converted into methyl 5,7,8,9,10,11-hexahydro-7-oxo-8,11-iminoazepino[1,2-b]isoquinoline-10-carboxylates.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 993 - 1007
Published online:
DOI: 10.3987/COM-94-S100
Computer-assisted Design of Syntheses for Heterocyclic Compounds

Ralf Fick, Wolf-Dietrich Ihlenfeldt, and Johann Gasteiger*

*Computer-Chemie-Centrum, Universität Erlangen-Nüernberg, Naegelsbachstr. 25 D-91052 Erlangen, Germany

Abstract

Fundamental strategies and search methods for the development of a synthesis plan for heterocyclic compounds are presented. These methods have been incorporated into the synthesis design system WODCA (Workbench for the Organization of Data for Chemical Applications). The use of this computer system is illustrated with several target compounds containing heterocycles of various degrees of complexity such as lysergic acid, 3-benzylpiperidine, and rotenone.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 1009 - 1014
Published online:
DOI: 10.3987/COM-94-S101
Synthesis and Excitatory Activitis of Some Aromatic Kainoids, Acromelic Acid Analogs

Manabu Horikawa, Yukiko Shima, Kimiko Hashimoto, and Haruhisa Shirahama*

*Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan

Abstract

The hydroxyiodophenyl, iodoanisyl and carboxyphenyl kainoids, (9, 10, and 13) were synthesized from the hydroxyphenyl compound (6). These new kainoids showed weak depolarizing activities in the preparation of a new-born rat spinal motoneuron.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 1015 - 1026
Published online:
DOI: 10.3987/COM-94-S102
Heterocyclization Reactions with α,β-Unsaturated Fluorine-containing Isothiocyanates: Reactions of Perfluoro-2-methyl-2-penten-3-yl Isothiocyanate with Enamines

Vera Ya. Popkova, Fyodor M. Dolgushin, Mikhail Yu. Antipin, Aleksandr I. Yanovsky, Yurii T. Struchkov, and Klaus Burger*

*Department od Organic Chemistry, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany

Abstract

A one-step synthesis of polyfluorinated 4,5-dihydro- and 2,5-dihydro-1,3-thiazoles starting from perfluoro-2-methyl-2-penten-3-yl isothiocyanate and enamines is described. The formation of 4,5-dihydro-1,3-thiazoles proceeds stereospecifically with respect to the exocyclic CC double bond.

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Paper | Special issue | Vol 40, No. 2, 1995, pp. 1027 - 1034
Published online:
DOI: 10.3987/COM-94-S103
α-Diketones in [4+2]Cycloadditions, Reactions of Dimethyl 2,3-Dioxosuccinate with Enol Ethers

Reiner Sustmann* and Michael Felderhoff

*Institut fur Organische Chemie, Universitat Essen, D-45117 Essen, Germany

Abstract

Dimethyl 2,3-dioxosuccinate (1) undergoes cycloaddition with enol ethers. Dihydrodioxine derivates, products of [4+2] cycloaddition, are formed with tetraethoxyethylene and E-1,2-dimethoxyethylene. The stereospecificity of the reaction of 1 with E-1,2-dimethoxyethylene suggests a concerted mechanism for this cycloaddition. The polarized double bond of ethyl vinyl ether reacts with 1 to give 4,5-dihydro-2,3-dimethoxycarbonyl-2,3-epoxy-5-ethoxyfuran in a hitherto unknown reaction of 1,2-diketones.

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Review | Special issue | Vol 40, No. 2, 1995, pp. 1035 - 1053
Published online:
DOI: 10.3987/REV-94-SR3
Charge Transfer Complexes in the Chemistry of Aromatic N-Oxides

Ludmila L. Rodina and Alexander V. Ryzhakov

*Department of Chemistry, St. Petersburg University, Srednij pr. 41, 199004, St. Petersburg, Russia

Abstract

Using nucleophilic substitution reactions in heteroaromatics (N-oxides) it was shown, that binding of substrate in donor-acceptor complex with appropriate acceptor decreases strongly the electron density in the nucleus of the starting compound, thus substantially facilitating the reactions with nucleophilic reagents. At the same time, the electrophilicity of heteroaromatic substrate increases owing to the partial electron density transfer to the Π-acceptor molecule, which remains covalently unbound with donor in the course of the reaction.

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Review | Special issue | Vol 40, No. 2, 1995, pp. 1055 - 1091
Published online:
DOI: 10.3987/REV-94-SR4
Connection between Metalation of Azines and Diazines and Cross-Coupling Startegies for the Synthesis of Natural and Biologically Active Molecules

Alain Godard, Francis Marsais, Nelly Plé, François Trécourt, Alain Turck, and Guy Quéguiner*

*Laboratoire de Chimie Organique Fine et Hétérocyclique, IRCOF - UPRES-A 6014, INSA, Université de Rouen, Place Emilae Blondel, BP 08,76131 Mont-Saint-Aignan Cedex, France

Abstract

When connected to transition metal catalyzed reaction, metalation becomes a very efficient tool for the synthesis of complex molecules. The methodology is applied to the preparation of some natural and biologically active molecules. The synthesis of streptonigrin models, orelline, azacarbazoles, ellipticine, bacimethrin analogues, trimethoprim and leshmanacides is presented here.

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51 data found. 31 - 51 listedFirst Previous