32136-52-0Relevant academic research and scientific papers
Improvements in Diels-Alder cycloadditions with some acetylenic compounds under solvent-free microwave-assisted conditions: Experimental results and theoretical approaches
Loupy, André,Maurel, Fran?ois,Sabatié-Gogová, Andrea
, p. 1683 - 1691 (2007/10/03)
The Diels-Alder irreversible cycloadditions of 1,3-cyclohexadiene 1, 3-carbomethoxy-2-pyrone 2 and 2-methoxythiophene 3 with acetylenic dienophiles under solvent-free conditions are described. By strict comparisons with conventional heating under similar conditions, important specific microwave effects are revealed in the two last cases whereas they are absent in the first one. They are discussed in terms of asynchronous mechanisms in agreement with ab initio calculations at the HF/6-31G(d) level indicating dissymmetries in transition states. Specific MW effects can be understood by considering the enhancements in dipole moments from ground states to transition states.
Diels-Alder reaction of methoxythiophenes: A new one-pot synthesis of dimethyl phthalates
Corral,Lissavetzky,Manzanares
, p. 29 - 31 (2007/10/03)
A series of dimethyl phthalates have been prepared from methoxythiophenes and dimethyl acetylenedicarboxylate (DMAD) in xylene. When the reaction is carried out in acetic acid, thienylfumarates are obtained.
Facile Interconversion of the Isomeric Acid Chlorides Derived from Half Methyl Esters of 3-Methoxyphthalic Acid
Gupta, Dahmendra N.,Hodge, Philip,Hurley, Peter N.
, p. 391 - 394 (2007/10/02)
The isomeric acid chlorides obtained by treating the half methyl esters of 3-methoxyphthalic acid with thionyl chloride interconvert so readily that it is not practical to isolate one acid chloride free of the other.At equilibrium the main isomer is the a
Syntheses of Highly Substituted Benzenes via Diels-Alder Reactions with 2H-Pyran-2-ones
Ziegler, Thomas,Layh, Marcus,Effenberger, Franz
, p. 1347 - 1356 (2007/10/02)
The 2H-pyran-2-ones (α-pyrones) 1 react as dienes in Diels-Alder reactions with acetylene derivatives.The primarely formed cycloadducts immediately aromatize to benzenes by CO2 elimination.Thus, methyl acetylenedicarboxylate (2a) gives dimethyl phthalates 3, and methyl acetylenediphosphonate (2b) gives dimethyl 1,2-phenylenediphosphonates 8.The reactions of 1-(dimethylamino)-1-methoxyethene (9) with 1 regioselectively produce N,N-dimethylanilines 10 and isomeric homophthalate derivatives 12.Naphthoquinones 14 could be generated from 1,4-benzoquinone (13) and 1 in the presence of acetic anhydride and Pd/C.Hydroxy-2H-pyran-2-ones 4 react via their trimethylsilyl ether 6 analogously with 2a to give dimethyl (trimethylsiloxy)phthalates 7 which are easily converted to phenols 5 by acid-catalyzed hydrolysis.
Regiospecific synthesis of anthracyclinone compounds such as daunomycinone
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, (2008/06/13)
A regiospecific synthesis for anthracyclinones asymmetric is disclosed. The synthesis is based upon a regiospecific bromination of the C-7 position of the α-tetralone which after transposing the keto group to the β-position and reaction with an organo-lithium compound is condensed with a phthalate ester.
(1E)-1,3-DIMETHOXY-1,3-BUTADIENE
Dowd, Paul,Weber, William
, p. 2155 - 2156 (2007/10/02)
Reaction of 1,1-dimethoxy-2-butyne (II) with sodium methoxide in dimethyl sulfoxide at 100 deg C yields (1E)-1,3-dimethoxybutadiene (III) (20-30percent).The diene III undergoes ready Diels-Alder reaction with maleic anhydride, N-phenytriazolinedione and d
Preparation and Reaction of Pyridones: Steric and Electronic Effects on Cycloadditions with 2(1H)-Pyridones
Gisby, Graham P.,Royall, Sven E.,Sammes, Peter G.
, p. 169 - 174 (2007/10/02)
The reactions of series of substituted 2(1H)-pyridones with dimethyl butynedioate have been studied.Cycloadditions across the 3,6-positions can be observed in certain instances and are particularly favoured where steric buttressing occurs between the substituent groups of the starting pyridones.The pyridone could not be induced to react with simple olefins, either by intermolecular or, via incorporation of alkenyl substituents, by intramolecular processes.From the results it is shown that 2-pyridones can be encouraged to behave as reactive classical dienes in cycloaddition reactions.
