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

Harris, Maria Inês N. C.; Braga, Antonio Claudio Herrera

doi:10.1590/s0103-50532004000600027

Cited by 22 publications

(9 citation statements)

References 13 publications

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“…The absolute configurations of the two newly created stereogenic centers were to be assigned based on the identification of the final generated product(s). Various methods including catalytic hydrogenations, 4b dissolving metal reduction, 17 and treatment with LiBH 4 /CeCl 3 18 or with NaBH 4 in glacial acetic acid 19 have been described to afford predominantly syn amino alcohols. We decided to perform the reduction with in situ generated sodium triacetoxy borohohydride in acetic acid, as this method had been successfully used in our laboratory to reduce pyrrolidine β-enamino ester 1 into the corresponding β-amino ester with a high diastereoselectivity.…”

Section: Resultsmentioning

confidence: 99%

New access to chiral pyrrolidine and piperidine β-enamino ketones. Application to the enantioselective synthesis of (–)-hygroline

Vanucci-Bacqué¹,

Calvet-Vitale²,

Fargeau-Bellassoued³

et al. 2007

Arkivoc

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Section: Resultsmentioning

confidence: 99%

New access to chiral pyrrolidine and piperidine β-enamino ketones. Application to the enantioselective synthesis of (–)-hygroline

Vanucci-Bacqué¹,

Calvet-Vitale²,

Fargeau-Bellassoued³

et al. 2007

Arkivoc

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“…40 γ-Amino alcohols are obtained in 70-98% yields in syn configuration predominantly (de 44-99%) as ascertained by analysis of the corresponding tetrahydro oxazine derivatives. The same authors have also patented this procedure.…”

Section: Scheme 14mentioning

confidence: 99%

Chemo- and stereoselective reduction of enaminones for the preparation of biologically active compounds

Palmieri¹,

Cimarelli²

2006

Arkivoc

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The chemistry of the preparation of β-enamino ketones and β-enamino esters and their use as useful starting materials in reductive procedures for the preparation of biologically active natural products is described.Enaminones are very stable compounds and can be easily prepared, starting from cheap and easily available starting materials. Therefore they constitute also excellent starting materials in organic synthesis. Several chemo-and regioselective methodologies for their preparation have been developed also recently. The possibility to use enantiopure chiral amines for the preparation of enamino ketones and enamino esters makes available useful starting materials for the preparation of enantiopure biologically active compounds. Moreover, it is possible to obtain more complex enaminones by regio-and stereoselective functionalization of the more accessible ones.Recently numerous methodologies for the chemo-and stereoselective reduction of enaminones have been developed, that constitute useful alternative pathways to the numerous literature procedures for the preparation of γ-amino alcohols, β-amino acids, aminoalkyl phenols and their derivatives. γ-Aminoalcohols and aminoalkylphenols are a class of very stable compounds that find useful applications in asymmetric catalysis as chelant for the preparation of chiral enantiopure metallic catalysts.

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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%

mentioning

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

Cited by 22 publications

References 13 publications

New access to chiral pyrrolidine and piperidine β-enamino ketones. Application to the enantioselective synthesis of (–)-hygroline

New access to chiral pyrrolidine and piperidine β-enamino ketones. Application to the enantioselective synthesis of (–)-hygroline

Chemo- and stereoselective reduction of enaminones for the preparation of biologically active compounds

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

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