Enaminones

Greenhill, John V.

doi:10.1039/cs9770600277

Cited by 417 publications

(204 citation statements)

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“…The E-isomers of similar enaminones are known to exhibit lower intensity carbonyl stretches at higher wavenumbers compared to the Z-isomers, due to the lack of intramolecular hydrogen bonding. 11,13 This shoulder therefore clearly indicated that both the Z-(1640 cm -1 ) and E-isomers (1669 cm -1 ) were formed during the reaction. Analysis of the full spectra showed that there were no obvious intermediate species, i.e.…”

Section: Resultsmentioning

confidence: 97%

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Conjugate Addition of 3-Buytn-2-one to Anilines in Ethanol: Alkene Geometric Insights through In Situ FTIR Monitoring

et al. 2016

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Publisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in The Journal of Organic Chemistry, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/acs.joc.6b01110. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractA convenient, mild and effective conjugate addition of 3-butyn-2-one to a variety of anilines in ethanol is reported. The reaction was monitored and characterized through in situ FTIR, and the dynamics of the facile E/Z alkene geometry interconversion of the resultant aniline-derived enaminones was explored through NMR, FTIR and Xray crystallography. A straightforward purification protocol that employs direct Kugelrohr distillation was identified and the method was further extended to other amines and ynones, allowing rapid access to these interesting compounds.

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Section: Resultsmentioning

confidence: 97%

“…11 We therefore anticipated that we could use in situ FTIR spectroscopy (ReactIR TM ), 12 to explore and follow the conjugate addition reaction in detail by tracking the loss of the ynone carbonyl stretch of 2a and the rise of the enaminone carbonyl stretch. Table 1.…”

Section: Resultsmentioning

confidence: 99%

Conjugate Addition of 3-Buytn-2-one to Anilines in Ethanol: Alkene Geometric Insights through In Situ FTIR Monitoring

et al. 2016

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“…10 The use of NaBH 4 in a carboxylic acid medium is well known, 16 but its use in the reduction of β-enamino ketones 2 has not been explored. Our results show that the reaction of β-enamino ketones 2 with NaBH 4 in glacial acetic acid (3 hours at room temperature, Scheme 1), produces a mixture of syn/anti γ-amino alcohols 1, the syn isomer being the major product (Table 1).…”

Section: Resultsmentioning

confidence: 99%

“…This functionality is found in several antibiotics and other biologically active natural products. 1 Several synthetic methods have been described for the synthesis of γ-amino alcohols 1 from diols, 2 hydroxazols, 3 lactams 4 and lactones, 5 but the more important methods are those where one can obtain γ-amino alcohols 1 by reduction of 1,3-difunctionalized unsaturated compounds containing nitrogen and oxygen, such as β-hydroxy oximes, 6 β-enamino ketones 2, [7][8][9][10][11] and, more frequently, by the reduction of β-amino ketones. 1,[12][13][14][15] γ-Amino alcohols 1, mainly syn, can be synthesized by reduction of β-enamino ketones 2 with Na in Pr i OH/ tetrahydrofuran or with CeCl 3 / LiBH 4 /tetrahydrofuran.…”

Section: Introductionmentioning

confidence: 99%

An easy and efficient method to produce gamma-amino alcohols by reduction of beta-enamino ketones

Harris¹,

Braga²

2004

J. Braz. Chem. Soc.

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“…An alternative method to obtain 1,3-oxazinanes is by cyclization of 1,3-amino alcohols with phosgene and aldehydes. 16,17 The access to 1,3-amino alcohols is usually done by the reduction of the respective β-enaminones or β-enamino esters, which are obtained from the reaction of amine with the corresponding 1,3-dicarbonyl compounds [18][19][20][21][22] or β-alkoxyvinyl ketones. [23][24][25][26][27][28][29][30] It has been reported that the introduction of a trifluoromethyl group in heterocycles frequently results in much more potent activity than that of the parent compounds, a fact that is probably related to the high lipophilicity of the trifluoromethyl group.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of N-substituted 6-trifluoromethyl-1,3-oxazinanes

Zanatta¹,

Squizani²,

Fantinel³

et al. 2005

J. Braz. Chem. Soc.

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Este trabalho apresenta a síntese de duas novas séries de 6-trifluormetil-1,3-oxazinanas N-substituídas e 6-trifluormetil-1,3-oxazinan-2-onas N-substituídas, a partir da ciclização de 4-ilamino-1,1,1-trifluor-butan-2-óis com formaldeído e trifosgênio, respectivamente. Os 4-ilamino-1,1,1-trifluor-butan-2-óis foram obtidos através da reação de redução dos precursores 4-ilamino-1,1,1-trifluor-but-3-en-2-onas, utilizando hidrogênio e 10% Pd/C, com bons rendimentos.This work reports the synthesis of two new series of N-substituted 6-trifluoromethyl-1,3-oxazinanes and N-substituted 6-trifluoromethyl-1,3-oxazinan-2-ones from the cyclization of 4-ylamino-1,1,1-trifluoro-butan-2-ols with formaldehyde and triphosgene, respectively. The 4-ylamino-1,1,1-trifluoro-butan-2-ols were obtained in good yields from the reduction of the parent 4-ylamino-1,1,1-trifluoro-but-3-en-2-ones with hydrogen and 10% Pd/C. Keywords: γ-amino alcohols, β-enamino ketones, 1,3-oxazinanes, 1,3-oxazinan-2-ones, 1,3-oxazines Introduction 1,3-Oxazines belong to a class of compounds that have been largely studied due to their wide range of biological activities and easy synthetic accessibility. Special attention has been given to these compounds since the development of Efavirenz, a trifluoromethyl-1,3-oxazin-2-one, which is a non-nucleoside reverse transcriptase inhibitor that shows high activity against a variety of HIV-1 mutant strains. 1 Although, 1,3-oxazinanes have not been used as extensively as the parent 1,3-oxazines, probably due to the difficulties to synthesize the saturated 1,3-oxazine ring with a wide range of substituents, 1,3-oxazinanes exhibit a variety of biological activities. Just to mention a few, they are being explored as anti-inflammatory and agents for treating ulcers, allergies, asthma, arthritis, and diabetes. 2 1,3-Oxazinanes have been used as key intermediates in the synthesis of thrombolytic agents, 3 liquid crystal devices, 4 chiral auxiliaries in organic synthesis, 5,6 and 1,3-amino alcohols, 7-10 and β-carbolines. 11 The synthesis of 1,3-oxazinanes, is much less developed than the parent 1,3-oxazines and there are not many available synthesis for 1,3-oxazinanes described in the literature. One of the first methods reported to synthesize 5-nitro-5-alkyl-1,3-oxazinanes, from the reaction of a primary nitroalkane with formaldehyde and ammonia or primary amines, was explored in the fifties and sixties. 12 Another method to synthesize 1,3-oxazinanes is by peracid-induced ring opening of isoxazolidines derived from the reaction of nitrones and alkenes. 13 A chiral approach to the synthesis of 1,3-oxazinan-2-ones utilizes aspartic acid as the starting material in a multistep procedure that includes the formation of an epoxide containing a Cbz-protected arylamine as the key intermediate. The synthesis continues with the epoxide ring opening by sodium azide followed by an intramolecular cyclization of the hydroxy group with the benzylcarbamate group to give the desired 1,3-oxazinan-2-one. 14 1,3-Oxazinan-2-ones were also obtain...

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Enaminones

Cited by 417 publications

References 0 publications

Conjugate Addition of 3-Buytn-2-one to Anilines in Ethanol: Alkene Geometric Insights through In Situ FTIR Monitoring

Conjugate Addition of 3-Buytn-2-one to Anilines in Ethanol: Alkene Geometric Insights through In Situ FTIR Monitoring

An easy and efficient method to produce gamma-amino alcohols by reduction of beta-enamino ketones

Synthesis of N-substituted 6-trifluoromethyl-1,3-oxazinanes

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