Trifluoroacetylation of unsymmetrical ketone acetals. A convenient route to obtain alkyl side chain trifluoromethylated heterocycles

Bonacorso, Hélio G.; Martins, Marcos A. P.; Bittencourt, Sandra R. T.; Lourega, Rogério V.; Zanatta, Nilo; Flores, Alex F. C.

doi:10.1016/s0022-1139(99)00146-3

Cited by 79 publications

(31 citation statements)

References 33 publications

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“…The in situ formation of kinetic enol ether under acylation conditions was discussed in a previous study. 19 Following the conventional route to CF 3 -containing 1H-pyrazole, the reaction of hydrazine hydrochloride with 1 in ethanol proceeded to give nearly quantitative yields of methyl 3-(5-trifluoromethyl-1H-pyrazol-3-yl)propanoate (2a). 16 For cyclocondensations between precursor 1 and amidine salts (hydrochloride or sulfate), we started the process based on a previous report on cyclocondensation [3 + 3] of 1,1,1-trifluoro-4-alkoxy-3-alken-2-ones and amidines under basic NaOH or alkoxy (methoxy, ethoxy) catalysis.…”

Section: Resultsmentioning

confidence: 99%

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Strategies for the Efficient Synthesis of Biheterocyclic 5-[2-(Trifluoromethylheteroaryl)-ethyl]-1,3,4-oxadiazoles from Levulinic Acid

Malavolta

Frigo

Moura

et al. 2017

J. Braz. Chem. Soc.

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The synthesis of 5-[2-(trifluoromethylheteroaryl)-ethyl]-1,3,4-oxadiazoles derived from levulinic acid is reported. Cyclocondensations [4 + 1] between four different 5- [2-(trifluoromethylheteroaryl) propionylhydrazides derived from methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate obtained from levulinic acid, and electrophilic orthoesters RC(OR 1 ) 3 (where R = H, Me, Ph) and CS 2 were carried out in a mild medium. Good yields (69-96%) of isolated products were obtained. The structures of the new ethylene-spaced biheterocycles were characterized using 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization coupled to tandem mass spectrometric (ESI MS/MS) data.

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Section: Resultsmentioning

confidence: 99%

“…Experimental 1 H, 13 C, 19 F NMR spectra were collected at 300 K using a Bruker 5 mm dual probe on a Bruker DPX 400 spectrometer ( 1 H at 400.13 MHz, 19 F at 376.4 MHz, 13 C at 100.62 MHz). Chemical shifts (d) are given in parts per million (ppm) from tetramethylsilane (TMS), and coupling constants (J) are given in Hz.…”

Section: Discussionmentioning

confidence: 99%

Strategies for the Efficient Synthesis of Biheterocyclic 5-[2-(Trifluoromethylheteroaryl)-ethyl]-1,3,4-oxadiazoles from Levulinic Acid

Malavolta

Frigo

Moura

et al. 2017

J. Braz. Chem. Soc.

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“…Figure S3. 1 H NMR spectrum from methyl 6-oxo-4-(2-phenylethyl)amino-7,7,7-trifluoro-4-heptenoate (3c), 400.13 MHz in CDCl 3 using TMS as internal standard. Figure S4.…”

Section: Supplementary Informationmentioning

confidence: 99%

“…54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 PROOF PROOF 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 Figure S5. 1 H NMR spectrum from methyl 6-oxo-4-phenylamino-7,7,7-trifluoro-4-heptenoate (3d), 400.13 MHz in CDCl 3 using TMS as internal standard.…”

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confidence: 99%

Efficient synthesis of new 1-[Alkyl(aryl)]-5-(3,3,3-trihalo-2-oxopropylidene)pyrrolidin-2-ones

Flores

Oliveira

et al. 2008

J. Braz. Chem. Soc.

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Este trabalho mostra a síntese, em bons rendimentos (57-95%), de duas séries de 1-alquil(aril) amino-2-oxo-5-(2-oxo-3,3,3-trialopropiliden)-pirrolidinas 5 e 6, a partir dos intermediários 4-[alquil(aril)amino]-6-oxo-7,7,7-trialo-4-hepteno-atos de metila 3 e 4 obtidos por substituição da metoxila-nos precursores 4-metoxi-6-oxo-7,7,7-trialo-4-heptenoatos de metila 1 e 2, pela série de aminas primárias RNH 2 , onde R = PhCH 2 , PhCH 2 CH 2 , Ph, 4-MeC 6 H 4 , 4-MeOC 6 H 4 , 4-ClC 6 H 4 , 4-BrC 6 H 4 , 2-piridnil, 5-metil-3-isoxazolil, 4-NH 2 C 6 H 4 . A estrutura molecular dos produtos inéditos foi atribuída a partir dos dados de RMN 1 H, 13 C e espectrometria de massas. A configuração geométrica dos compostos 3d e 5b foi confirmada pelos dados de difração de raios-X em monocristal.Reactions of methyl 4-methoxy-6-oxo-7,7,7-trihalo-4-heptenoates 1 and 2 with primary amines RNH 2 , where R = PhCH 2 , PhCH 2 CH 2 , Ph, 4-MeC 6 H 4 , 4-MeOC 6 H 4 , 4-ClC 6 H 4 , 4-BrC 6 H 4 , 2-pyridyl, 5-methyl-3-isoxazolyl, 4-NH 2 C 6 H 4 affording methyl 4-[alkyl(aryl)amino]-6-oxo-7,7,7-trihalo-4-heptenoates 3, 4, in good yields (57-95%), which suffer quantitative intramolecular cyclocondensation to produce 1-alkyl(aryl)-5-(2-oxo-3,3,3-trihalopropylidene)pyrrolidin-2-ones 5, 6, are reported. The structures of the isolated new products were assigned by means of 1 H, 13 C NMR measurements and mass spectrometry. The Z and E configuration of compounds 3d and 5b respectively were established from X-ray crystallography.

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“…7,8 Thus 2-perfluoroacylcycloalkanones are important molecules, which offer a variety of pathways in inorganic and organic synthesis, as all the perfluoroalkyl substituted 1,3-dicarbonyl compounds these are versatiles building blocks for regiospecific heterocyclic synthesis and have high affinity for diverse metallic cations in coordination chemistry. [9][10][11][12][13][14][15] The most employed method to obtain 2-perfluoroacylcycloalkanones is using alkaline acylation of enolates with perfluoroalkanoates. 1,3 As a part of our research program, we have developed general acetal acylation method for synthesis of 1,1,1-trihalo-4-alkoxy-3-alken-2-ones and demonstrated their hydrolysis to trihalomethyl-β-diketones, the procedure signify an acid acylation method.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of the omega-brominated alpha-trifluoroacetylcycloalkanones and their isoxazole derivatives

Flores¹,

Peres²,

Piovesan³

et al. 2006

J. Braz. Chem. Soc.

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Trifluoroacetylation of unsymmetrical ketone acetals. A convenient route to obtain alkyl side chain trifluoromethylated heterocycles

Cited by 79 publications

References 33 publications

Strategies for the Efficient Synthesis of Biheterocyclic 5-[2-(Trifluoromethylheteroaryl)-ethyl]-1,3,4-oxadiazoles from Levulinic Acid

Strategies for the Efficient Synthesis of Biheterocyclic 5-[2-(Trifluoromethylheteroaryl)-ethyl]-1,3,4-oxadiazoles from Levulinic Acid

Efficient synthesis of new 1-[Alkyl(aryl)]-5-(3,3,3-trihalo-2-oxopropylidene)pyrrolidin-2-ones

Synthesis of the omega-brominated alpha-trifluoroacetylcycloalkanones and their isoxazole derivatives

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