Special Issue

Alan R. Katritzky's Special Issues, Vol. 37, No. 3, 1994

56 data found. 31 - 56 listedFirst Previous
Paper | Special issue | Vol 37, No. 3, 1994, pp. 1705 - 1710
Published online:
DOI: 10.3987/COM-93-S140
Acid Catalyzed α-Pyrone Ring Formation Reactions

Cihangir Tanyeli, Ayhan S. Demir, Özdemir Özarslan, Idris Mecidoglu, and Okan Tarhan*

*Middle East Technical University, Department of Chemistry, 06531 Ankara, Turkey

Abstract

The reaction of 1,3-dicarbonyl compounds with methyl 2-carbomethoxy-3-(N-methylanilino)acrylate under acidic condition directly gives substituted 2H-pyran-2-ones in good yield.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1711 - 1718
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DOI: 10.3987/COM-93-S141
Heterocyclic Tautomerism. VIII. X-Ray Crystal Structures of Two Substituted 2-Methylenethiazolidin-4-ones

James A. M. Guard and Peter J. Steel*

*Department of Chemistry, University of Canterbury, Christchurch, New Zealand

Abstract

Location and refinement of the hydrogen atoms in low temperature crystal structure determinations have unambiguously established the tautomeric structures of two title compounds in the solid state. Both the carbamoyl (3) and benzoyl (4) derivatives exist as N-H tautomers with a Z-substituted exocyclic double bond. In both cases the carbonyl oxygen of the substituent is coplanar with the ring and in an scis conformation. The acetamide (3a) crystallises with two molecules in the asymmetric unit and packs with a complex network of intermolecular hydrogen bonds. Bond lengths in the benzoyl derivative (4a) suggest a contribution to the structure from a charged form.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1719 - 1729
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DOI: 10.3987/COM-93-S143
Auxiliary-controlled Site Selectivity [4+2] Cycloaddition Reactions of α,β-Unsaturated Carbonyl Compounds to 4,4-Bis(trifluoromethyl)-substituted Hetero-1,3-Dienes

Klaus Burger* and Jörg Cyrener

*Institut für Organische Chemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany

Abstract

[4+2] Cycloaddition reactions of α,β-unsaturated carbonyl compounds to 4,4-bis(trifluoromethyl)-1-hetero-3-azabuta-1,3-dienes occur exclusively across the carbon-oxygen double bond. A complete change of site selectivity is observed in the presence of equimolar amounts of 4-dimethylaminopyridine (DMAP).

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1731 - 1746
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DOI: 10.3987/COM-93-S144
Hammick Cyclizations Studies on the Mechanism of the Hammick Reaction

Bernhard Bohn, Nikolaus Heinrich, and Helmut Vorbrüggen*

*Process Research, Schering AG-Berlin, D-13342 Berlin, Germany

Abstract

Heating of 3-hydroxypicolinic acid with the acetyketene precursor 2,2,4-trimethyldioxin-4-one, ethyl acetoacetate or ethyl 2-cyclopentanonecarboxylate leads via the 3-O-acylated 3-hydroxypicolinic acids, which cannot be isolated, and subsequent decarboxylation to the corresponding Hammick cyclization products in up to 25% yield besides 3-hydroxypyridine. In the case of 3-aminopicolinic acid the 3-(3-oxobutyrylamido)picolinic acid can be isolated but gives on heating only 3-aminopyridine and 3-(3-oxobutyrylamido)pyridine albeit none of the anticipated Hammick cyclization products. The Hammick cyclization reactions, side reactions and reaction mechanisms are discussed.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1747 - 1759
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DOI: 10.3987/COM-93-S145
Synthesis of Phenanthridinium Ylides

M. Teresa Gandásegui, Julio Alvarez-Builla*, and Feliciana Florencio

*Departamento de Química Orgánica, Universidad de Alcalá de Henares, E-28871 Alcalá de Henares, Madrid, Spain

Abstract

Reaction of phenanthridinium methylides with several dipolarophiles, yielding disubstituted ylides in most of the examples, is described.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1761 - 1772
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DOI: 10.3987/COM-93-S147
Vinylation of the Indole 3-Position via Palladium-catalyzed Cross-Coupling

Qi Zheng, Youhua Yang, and Arnold R. Martin*

*Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ 85721, U.S.A.

Abstract

The palladium-catalyzed cross-coupling between 3-indoleboronic acids and vinyl triflates is an excellent method for the regioselective introduction of vinyl groups into the indole 3-position. The regioselectivity of the enolization of N-substituted 3-piperidones, as dictated by the nitrogen substituent, is far greater than previously reported. N-tosyl-3-indoleboronic acids can be easily synthesized using the mercuration-boronation method.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1773 - 1788
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DOI: 10.3987/COM-93-S148
Controlling Stereochemistry in Radical Addition and Cyclization Reactions with Oppolzer's Camphor Sultam

Dennis P. Curran,* Wang Shen, Jiancun Zhang, Steven J. Gieb, and Chien-Hsing Lin

*Department of Chemistry, University of Pittsburgh, Parkman Avenue & University Drive Pittsburgh, PA 15260, U.S.A.

Abstract

Acrylate derivatives of Oppolzer’s camphor sultam exhibit good to excellent Ievels ol stcreoselectiviy in typical radical allkylations and alkene and alkyne cyclizations.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1789 - 1805
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DOI: 10.3987/COM-93-S149
Development of Methodology Based on the Use of the 7-Oxabicyclo[2.2.1]heptanyl System for the Preparation of carbohydrate Derivatives

David J. Ager* and Michael B. East

*Nutra Sweet Research and Development, 601 E. Kensington Road, Mount Prospect, Illinois 60056, U.S.A.

Abstract

The 7-oxabicyclo[2.2.1]heptanyl system provides 2 rapid entry to carbohydrate derivatives in a stereoselective manner by virtue of the rigid framework. The formation of this bicyclic system through a Diels-Alder reaction of furan with a number of dienophiles is influenced by the substitution on the dienophile. Use of an anion stabilising group as a carbonyl equivalent has previously led to a ring opening reaction of the bicyclic system. However, anion chemistry can be used to functionalise the bicyclic system, and used for the introduction of a hydroxy group that allows, in turn, a method for the preparation of hexose derivatives.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1807 - 1817
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DOI: 10.3987/COM-93-S151
Construction of 12-Azaeburnane Skeleton: Synthesis of Ethyl 12-Azaaprovincaminate

László Ürögdi,* Gizella Barta-Szalai, Lajos Kisfaludy, György Domány, and Attila Csehi

*Spectroscopic Research Division, Chemical Works of Gedeon Richter Ltd., Budapest 10, P. O. Box 27, H-1475 Budapest, Hungary

Abstract

A synthesis of 12-azaeburnane skeleton is described. The synthetic sequence has been successfully applied to the preparation of 12-aza analogue of the cerebral vasodilator, ethyl apovincaminate (CavintonR) and some related derivatives.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1819 - 1826
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DOI: 10.3987/COM-93-S152
1H NMR Chemical Shift of the Isoflavanone 5-Hydroxyl Proton as a Characterization of 6- or 8-Prenyl Group

Toshio Fukai, Liming Tantai, and Taro Nomura*

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

Abstract

1H Nmr examination of 6- or 8-prenylated isoflavanone derivative has shown that the location of prenyl side chain on A ring can be deduced from the chemical shift of the 5-hydroxyl proton. The effects of substituents of B ring for the chemical shift are also discussed.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1827 - 1851
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DOI: 10.3987/COM-93-S153
Organic Heterocyclothiazenes. Part 19. Synthesis of 1,3,2-Dithiazoles Using Bis(chlorothio)nitronium Tetrachloroaluminate, [N(SCl)2][AlCl4]

Michael A. Gray, Charles W. Res,* and David J. Williams

*Department of Chemistry, Imperial College of Science, Technology and Medicine, GB-London SW7 2AY, U.K.

Abstract

Reaction of the readily prepared bis(chlorothio)nitronium tetrachloroaluminate (4) with electron-rich arylacetylenes in dichloromethane at room temperature leads to a cycloaddition reaction resulting in 4-aryl-1,3,2-dithiazolium salts (5) which when treated in situ with base afford 5-aryl-1,3,2-dithiazole-4-thiones (6). The scope of this reaction with other alkenes and alkynes is described. No reaction was observed with the electron-deficient 4-nitrophenylacetylene. The conjugated thione (17) was also formed in the reaction of an old specimen of salt (4) with phenylacetylene. Treatment of salt (4) with 1,2-dichloroethylene followed by aniline gave a minor amount of the novel dimer (20). The reaction of acetophenone oxime with disulfur dichloride provides a route to the salt (26) which on treatment with water or aniline affords 4-phenyl-1,2,3-dithiazol-5-one (23) and 4-phenyl-5-phenylimino-1,2,3-dithiazole (27) respectively. 14N Nmr studies are shown to be useful in distinguishing between 1,2,3- and 1,3,2-dithiazoles. X-Ray crystal structures are presented for compounds (17,20,27), and 5-anilino- 1,3,2-dithiazole-4-thione (18).

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1853 - 1864
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DOI: 10.3987/COM-93-S154
The Synthesis of (S) and (R) Enantiomers of Novel Hydroxymethylated Isodideoxynucleosides

Lawrence B. Zintek, Geun Sook Jeon, and Vasu Nair*

*Department of Chemistry, The University of iowa, Iowa City, Iowa 52242, U.S.A.

Abstract

Novel isomeric diioxynucleosides, with symmetry introduced at the 2’-position (4’-position using normal nucleoside numbering) through the introduction of an additional hydroxymethyl group, have been synthesized. Both (R) and (S) enantiomeric series were investigated. The methodologies developed have generality and the presence of the hydroxymethyl group trans to the base may be used to inducea wide variety of functionalities at this position.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1865 - 1872
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DOI: 10.3987/COM-93-S158
Synthesis of a Novel Macrocyclic Lactone System

Keith Smith,* Ian K Morris, and Robert J. Bass

*Department of Chemistry, University College of Swansea, Singleton Park, Swansea SA2 8PP, U.K.

Abstract

A total synthesis of a 14-membered ring lactone (3) with potential biological activity is described. The final lactonization step uses a modification of the Corey pyidinethiol ester procedure.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1873 - 1878
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DOI: 10.3987/COM-93-S160
1-Arylamino-2,3-dihydro-1H-imidazole-2-thiones from the Reaction of 1-[2-(2-Arylhydrazono)alkyl]pyridinium Iodides with Potassium Thiocyanate

Joachim G. Schantl,* Hanspeter Kählig, and Michael Prean

*Institut für Organische Chemie, Universität Innsbruck, Innrain 52, A-6020 Innsbruck, Austria

Abstract

The conversion of 1-[2-(2-arylhydrazono)alkyl]pyridinium iodides (1) with potassium thiocyanate into 1-arylamino-2,3-dihydro-1H-imidazole-2-thiones (4) is envisaged to result from the [3+2] cycloaddition reaction of intermediate arylazoalkenes (2) and thiocyanic acid via the azomethine imine cycloadducts (3) followed by 1,4-hydrogen shift.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1879 - 1891
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DOI: 10.3987/COM-93-S162
A Novel Synthesis of 3,3-(Spiro)substituted Azetidines

Johannes Fröhlich, Fritz Sauter,* and Krain Blasl

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

Abstract

A smooth and efficient new synthesis for 3,3-disubstituted azetidines, starting from readily available nitriles, was established: α-hydroxymethylation of the starting materials, followed by O-tosylation and LiAIH4-reduction of the key intermediates thus obtained, led - via spontaneous cyclization of the intermediate amino derivatives - to 3,3-disubstituted azetidines. Scope and limitations of this new method were studied with respect to generalized applicability: the target compounds were accessible in good yields for a variety of starting materials (cyclic and acyclic di(hetero)aryl, (hetero)arylalkyl, dialkyl, as well as basic moieties). The products thus obtained may be of interest for ensuing conversions due to their unblocked nitrogen.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1893 - 1912
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DOI: 10.3987/COM-93-S163
Synthesis of (±)-Fredericamycin A

A. V. Rama Rao,* Ashok Kumar Singh, Batchu Venkateswara Rao, and Komandla Malla Reddy

*Indian Institute of Chemical Technology, Hyderabad 500 007, India

Abstract

A total synthesis of fredericamycin A (1) is described, in which a novel radical cyclisation approach is used to build the spiro[4.4]nonane system. The supporting studies with experimental details are reported.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1913 - 1932
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DOI: 10.3987/COM-93-S164
Preraration and Photolysis of 1-Heterosubstitute 1-(1-Alkenyl)benzotriazoles

A. Peter Johnson,* Jonathan K. Dutton, and David P. M. Pleynet

*School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.

Abstract

A Peterson olefination reaction involving 1-trimethylsilanylmethyl-1H-benzotriazole and either adamantanone or acetone, in the presence of n-butyllithium, is used to prepare 1-adamantylidenemethyl-1H-benzoeiazolea nd 1-(2-methylpropenyl)-1H-benzotriazole respectively. Further treatment of these compounds with n-butyllithium and an electrophile affords a variety of 1-heterosubstituted 1-(1-alkenyl)benzotriazoles. Photolysis of the latter compounds yields products from three competing pathways: cyclisation with C-C bond formation, cyclisation with C-S bond formation and halogen atom transfer.

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Paper | Special issue | Vol 37, No. 3, 1994, pp. 1933 - 1950
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DOI: 10.3987/COM-93-S165
Short Interactions between Heterocyclic Sulfer Atoms and Thiocarbonyl Sulfer or Carbonyl Oxygen Atoms

Robert F. Hudson,* John D. Wallis, and David P. Hansell

*Chemical Laboratory, University of Kent, Canterbury, Kent CT2 7NH, U.K.

Abstract

Short intramolecular S---S=C contacts in N-(2-thiazolylidene)-benzenecarbothioamides (11 and 12), 0.60A less than the corresponding separation predicted by Van der Waals radii, are accounted for by Coulombic interactions and 3d orbital participation as a result of electron delocalisation within each molecule. Similar considerations apply to S---O=C contacts, however short S---S intermolecular interactions between sulfides are due to the asymmetric electron distribution about the bonded sulfide atoms.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 1951 - 1975
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DOI: 10.3987/REV-93-SR11
Approches to the Synthesis of 1-Substituted 1,2,4-Triazoles

Marudai Balasubramanian, James G. Keay, Eric F. V. Scriven,* and Navayath Shobana

*Reilly Industries, Inc., 1500 S. Tibbs Avenue, Indianapolis, Indiana IN 46242, U.S.A.

Abstract

This review summarizes the main methods currently available for the synthesis of 1-substituted 1,2,4-triazoles.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 1977 - 2008
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DOI: 10.3987/REV-93-SR13
Pyrrolizin-3-ones

Hamish McNab* and Craig Thornley

*Department of Chemistry, The University of Edinburgh, King's Buildings, West Mains Road Edinburgh, EH9 3JJ, U.K.

Abstract

The preparation, and physical and chemical properties of the pyrrolizin-3-one system (1) and its 1,2-dihydro derivatives (2) are reviewed.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 2009 - 2027
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DOI: 10.3987/REV-93-SR15
Optimization of Synthesis of Nitroimidazoles and Nitropyrazoles Based on Polarographic Investigations

D. Dumanovic,* Dj. Kosanovic, and P. Zuman

*ICN Galenika Institute, 29., Novembar 111, 11000 Belgrade, Yugoslavia

Abstract

Direct, simple, fast, and inexpensive polarographic method enables selective determinations of nitroimidazoles or nitropyrazoles (nitroazoles) in mixtures which can be used for monitoring synthetic processes and selecting optimal conditions for synthesis.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 2029 - 2049
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DOI: 10.3987/REV-93-SR16
Relative Stabilities of Hetarenium Ions: Factors Controlling Positional Selectivities of Electrophilic Substitution and Acid-induced Transformations of Pyrrole, Furan and Thiophene Derivatives

Leonid I. Belen'kii*

*N.D.Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 117913, Moscow, Russia

Abstract

Positional selectivity in electrophilic substitution reactions of pyrrole, thiophene and furan derivatives including methods of orientation control as well as stability and some transformations of hetarenium ions are reviewed.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 2051 - 2068
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DOI: 10.3987/REV-93-SR19
Synthesis of Heterocycles from Aminoamide Oximes

Dezsö Korbonits* and Károly Horváth

*CHINOIN Pharmaceutical and Chemical Works Ltd., P. O. Box 110, H-1325 Budapest, Hungary

Abstract

Syntheses of nitrogen heterocycles starting from aminoamide oximes involving heterocyclic rearrangements including novel types of ring-chain tautomerism of pyrimidines are reviewed.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 2069 - 2086
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DOI: 10.3987/REV-93-SR22
Heterocycle-based Electric Conductors

Giorgio A. Pagani*

*Dipartimento di Chimica Organicane Industriale, dell'Universitè, Via Golgi 19, I-20133 Milano, Italy

Abstract

A review is presented of our contribution addressed towards: i) the control of redox potentials of pyrrole- and thiophene-based conductors and ii) the search for polythiophene models. We approached the first by exploiting the spacer strategy, according to which the monomer contains two terminal polymerogenic units linked to a central Π-conjugatively active frame. The second topic was approached by investigating end-methyl-capped thiophene oligomers. Taken together, the results clear up many puzzling aspects and provide influential clues for designing tailored heterocyclic structures that respond to specific operational requirements.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 2087 - 2147
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DOI: 10.3987/REV-93-SR23
Synthesis and Reactions of Lithiated Monocyclic Azoles Containing Two or More Hetero-Atoms. Part III: Pyrazoles

M. Ross Grimmett and Brian Iddon*

*The Ramage Laboratories, Department of Chemistry and Applied Chemistry, University of Salford, Salford M5 4WT, U.K.

Abstract

The metallation and halogen → metal exchange reactions of pyrazoles (1,2-diazoles) and the reactions of the resulting organometallic derivatives, particularly lithiafed derivatives, are reviewed comprehensively.

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Review | Special issue | Vol 37, No. 3, 1994, pp. 2149 - 2172
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DOI: 10.3987/REV-93-SR20
Metalation of Diazines

Alain Turck, Nelly Plé, and Guy Quéguiner*

*URA 1429, Laboratoire de Chimie Organique Heterocyclique, INSA-IRCOF-BP 08, F-76131 Mont St Aignan Cedex, France

Abstract

The metalation of diazines has been recently developed, below are reported the main results in this area of research.

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56 data found. 31 - 56 listedFirst Previous