Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/2016

TitleSonogashira cross-couplings of dehydroamino acid derivatives and phenylacetylenes
Author(s)Abreu, Ana S.
Ferreira, Paula M. T.
Queiroz, Maria João R. P.
Gatto, Emanuela
Venanzi, Mariano
KeywordsAmino acids
Phenylacetylenes
Sonogashira coupling
Palladium
Benzo[b]thiophenes
Fluorescence
Issue date2004
PublisherWiley
JournalEuropean Journal of Organic Chemistry
Citation"European journal of organic chemistry". (2004) 3985-3991.
Abstract(s)Several phenylacetylenes were coupled under Sonogashira cross coupling conditions with the methyl esters of N-(tert-butoxycarbonyl)-(E)-beta-bromo or beta, beta-dibromodehydroalanine to give respectively beta-substituted or beta,beta-bis-substituted dehydroalanines. The beta-substituted dehydroalanines were obtained in good to high yields (60-90%) under the usual Sonogashira conditions (1 equiv. of the phenylacetylene, 1 mol% Pd(PPh3)4, 2 mol% CuI 18 equiv. NEt3 in acetonitrile, 24h at rt) with maintenance of the stereochemistry. The beta,beta-bis-substituted dehydroalanines were in turn obtained in moderate to good yields (44-63%) requiring modified Sonogashira conditions (4 equiv. of the phenylacetylene,10 mol% PdCl2(PPh3)2, 20 mol% CuI, 1.4 equiv. Cs2CO3, 2h at reflux of acetonitrile). In the latter reactions some phenylacetylene dimer and the (E)-isomer of the mono substituted coupled products were also isolated in some extent. The Sonogashira products which were obtained from the 4-bromophenylacetylene were reacted with functionalized benzo[b]thiophenes under C-C or C-N palladium-catalyzed cross-coupling conditions. Preliminary fluorescence studies were performed for mono and disubstituted 4-aminophenylacetylenic dehydroamino acids and for the benzo[b]thiophene derivatives. The results showed that some of the dehydroalanines prepared can be used as fluorescent probes.
TypeArticle
URIhttp://hdl.handle.net/1822/2016
DOI10.1002/ejoc.200400145
ISSN1434-193X
Peer-Reviewedyes
AccessOpen access
Appears in Collections:CDQuim - Artigos (Papers)

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