Dioxopyrrolines. XXVII. Syntheses of 2-aryl-3-ethoxycarbonyl-.DELTA.2-pyrroline-4,5-diones.

Sano, Takehiro; Horiguchi, Yuji; Toda, Jun; Imafuku, K.; Tsuda, Yoshisuke

doi:10.1248/cpb.32.497

Cited by 41 publications

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“…15 Some improved procedures have been also reported to utilize protonic acids such as HCl, 16 2 36 have been employed to promote this reaction. This condensation reaction has also been performed in water.…”

Section: Introductionmentioning

confidence: 99%

Cobalt(II) chloride-mediated synthesis of beta-enamino compounds under solvent-free conditions

Zhang¹,

Hu²

2006

J. Braz. Chem. Soc.

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Uma variedade de β-enaminonas e β-enamino ésteres foi sintetizada pela reação de compostos 1,3-dicarbonílicos com aminas na presença de quantidade catalítica de cloreto de cobalto(II), à temperatura ambiente na ausência de solventes. O procedimento experimental é simples e os produtos são isolados em altos rendimentos.A variety of β-enaminones and β-enamino esters can be synthesized by the reaction of 1,3-dicarbonyl compounds with amines in the presence of a catalytic amount of cobalt(II) chloride at room temperature under solvent-free condition. The experiment procedure is simple, and the products are straightforwardly isolated in high yields.Keywords: β-enaminones, β-enamino esters, 1,3-dicarbonyl compounds, amines, cobalt(II) chloride, solvent-free conditions Introduction β-Enaminones have attracted much attention due to the fact that they are important synthons for the synthesis of many biologically active compounds such as dopamine auto-receptor agonists, 1 acetylcholinestersase inhibitors 2 and anticonvulsants. 3 They are also useful intermediates for the preparation of several aminoacids, 4 aminols, 5 peptides and alkaloids. 6 Thus it is very important to search for a convenient and efficient method for the synthesis of this type of compounds. 7 Several methods have been developed for their synthesis including the reactions of imidoyl chlorides with acetonyltributyltin in the presence of palladium catalyst, 8 the addition of amines to acylacetylenes, 9 acylation of metalated ketimines using acylbenzotriazoles as acylating agents, 10 the reactions of lithiated enamines with diethyl carbonate or benzyl chloroformate, 11 the addition of ester or amide enolates to nitriles, 12 palladium-assisted amination of α-keto olefins 9 or amination with O-methylhydroxylamines in the presence of base, 13 and the reactions of alkyl azides and β-ketoesters in a one-pot procedure using 10% Pd/C catalyst and hydrogen.14 However, the most commonly used and straightforward approach for the preparation of these compounds is the direct condensation of β-dicarbonyl compounds and amines, in which the azeotropic removal of water is usually required under reflux using a Dean Stark trap in aromatic solvent. 15 organic transformations will be quite useful. As a part of our ongoing program in developing various new synthetic transformations using cheap and eco-friendly materials as catalysts, 39 we herein wish to report our results on the synthesis of β-enaminones and β-enamino esters using a catalytic amount of CoCl 2 ·6H 2 O at room temperature under solvent-free condition (Scheme 1). Results and DiscussionOur initial studies were focused on the optimization of the reaction conditions for the synthesis of β-enamino esters. Ethyl acetoacetate was chosen as a model substrate for the optimization process. The reaction of ethyl acetoacetate with aniline in the presence of 5 mol% CoCl 2 ·6H 2 O at room temperature, without any solvent, afforded the target ethyl 3-(phenylamino)but-2-enoate (3e) in 95% yield. Lower catalyst loading ca...

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Section: Introductionmentioning

confidence: 99%

Cobalt(II) chloride-mediated synthesis of beta-enamino compounds under solvent-free conditions

Zhang¹,

Hu²

2006

J. Braz. Chem. Soc.

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“…It was subsequently found that treatment of either of these compounds with ethyl mercaptopyruvate under ambient conditions in the presence of triethylamine resulted in the generation of the thiophene 6 in almost identical yields, suggesting that elimination of HBr from 4 precedes reaction with the thiol. Subsequent attempts to cyclize the amino ketoester 6 to generate the thienopyrrolidinedione 7 proved unsuccessful, a finding consistent with the limited number of reports extant in the literature for this type of vinylogous amide-ester cyclization [21][22][23]. In an attempt to increase the nucleophilicity of the amino functionality in 6, the arylketone moiety was reduced using triethylsilane under acidic conditions [24] to give the aminoester 8 in 77% yield.…”

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confidence: 56%

A novel route to the 5,6-dihydro-4-H-thieno[3,2-b]pyrrol-5-one ring system involving an intermediate substituted-thiophene synthesis

Hu¹,

Huang²,

Poss³

et al. 2005

Journal of Heterocyclic Chemistry

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“…We carried out the reaction of 5-phenyl-4-ethoxycarbonyl-1H-pyrrole-2,3-diones Ia-Id [4] with substituted acetonitriles [malononitrile (IIa) and methyl cyanoacetate (IIb)] and dimedone in the ratio 1 : 1 : 1 by boiling the solution of the reagents in anhydrous benzene in the presence -------------------* For Communication LXXVIII, see [1]. ** For preliminary communication, see [5].…”

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confidence: 99%

Five-membered 2,3-dioxoheterocycles: LXXIX. Three-component condensation of 1H-pyrrol-2,3-diones with acetonitriles and dimedone. Crystal and molecular structure of substituted spiro[chromene-4,3′-pyrrole]

et al. 2011

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5-Phenyl-4-ethoxycarbonyl-1H-pyrrole-2,3-diones react with acetonitriles and dimedone to form ethyl 2-amino-7,7-dimethyl-2',5-dioxo-5'-phenyl-1',2',5,6,7,8-hexahydrospiro[chromene-4,3'-pyrrole]-4'-carboxylates. The crystal and molecular structure of ethyl 2-amino-1'-benzyl-7,7-dimethyl-2',5-dioxo-5'-phenyl-3-cyano-1 ',2',5,6,7,8-hexahydrospiro[chromene-4,3'-pyrrole]-4'-carboxylate was proved by XRD analysis.

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Dioxopyrrolines. XXVII. Syntheses of 2-aryl-3-ethoxycarbonyl-.DELTA.2-pyrroline-4,5-diones.

Cited by 41 publications

References 0 publications

Cobalt(II) chloride-mediated synthesis of beta-enamino compounds under solvent-free conditions

Cobalt(II) chloride-mediated synthesis of beta-enamino compounds under solvent-free conditions

A novel route to the 5,6-dihydro-4-H-thieno[3,2-b]pyrrol-5-one ring system involving an intermediate substituted-thiophene synthesis

Five-membered 2,3-dioxoheterocycles: LXXIX. Three-component condensation of 1H-pyrrol-2,3-diones with acetonitriles and dimedone. Crystal and molecular structure of substituted spiro[chromene-4,3′-pyrrole]

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