Please use this identifier to cite or link to this item: https://hdl.handle.net/1822/72914

TitleSynthesis of substituted oxazoles from N-acyl-beta-hydroxyamino acid derivatives
Author(s)Ferreira, Paula M. T.
Monteiro, Luís S.
Pereira, Goreti
KeywordsAmino acids
Dehydroamino acids
Iodine
Cyclization
Oxygen heterocycles
Nitrogen heterocyles
Issue dateSep-2008
PublisherWiley-VCH Verlag
JournalEuropean Journal of Organic Chemistry
Abstract(s)Several N-acyl-beta-hydroxyamino acids were prepared and treated with di-tert-butyl dicarbonate in the presence of 4-(dimethylamino)pyridine, followed by treatment with N,N,N',N'-tetramethylguanidine to give the corresponding N-acyldehydroamino acids in good to high yields. These were then treated with I-2/K2CO3 followed by 1,8-diazabicyclo[5.4.0]undec-7-ene. The methyl esters of N-acyldehydroaminobutyric acid gave the corresponding substituted oxazoles in good to high yields. The N-acyldehydrophenylalanines gave 5-phenyloxazole derivatives in low to moderate yields together with beta-iododehydrophenylalanines. Under the same conditions, N-acyldehydroalanines failed to give the corresponding oxazoles. However, when the reaction was carried out in the absence of DBU, it was possible to isolate the beta,beta-diiododehydroalanine derivatives. Although the reason for the different reactivities of the N-acyldehydroamino acids is not completely clear to us, cyclic voltammetry studies showed that the less-reactive derivatives have higher reduction potentials. This suggests that the double bonds in dehydroaminobutyric acid derivatives are more susceptible to electrophilic attack by iodine. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).
TypeArticle
URIhttps://hdl.handle.net/1822/72914
DOI10.1002/ejoc.200800602
ISSN1434-193X
Publisher versionhttps://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/ejoc.200800602
Peer-Reviewedyes
AccessOpen access
Appears in Collections:CDQuim - Artigos (Papers)

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