Encontrados 10 documentos, a visualizar página 1 de 1
Avaliação Nutricional de Crianças com Doença Celíaca Seguidas na Consulta de Ga...
Silva, D.; Guerra, A. J.; Lemos, A.; Lourenço, S.; Amil, J.; Trindade, E.; Aguiar, A.; Santos, N. TeixeiraA doença celíaca (DC) tardiamente diagnosticada pode levar a um quadro de desnutrição grave. O seu tratamento limita-se à instituição de dieta isenta de glúten, aspecto nem sempre respeitado com rigor pelos doentes.O presente trabalho tem como principal objectivo avaliar o cumprimento da dieta e a sua repercussão nutricional em doentes celíacos. Foram incluídas 72 crianças que frequentam a consulta externa de G...
Cycloaddition reactions of nitrosoalkenes, azoalkenes and nitrile oxides mediat...
Lemos, A.; Lourenço, J. P.Mg:Al 3:1 hydrotalcite (Ht), used in catalytic quantities, promotes the generation of nitrosoalkenes, azoalkenes and nitrile oxides. These can be intercepted in situ by heterocycles and olefins in [4+2] and [3+2] cycloaddition reactions, producing dihydro-1,2-oxazines, tetrahydropyridazines and isoxazolines. The regeneration and reuse of Ht without loss of activity and the absence of organic solvent are the mai...
Cycloaddition reactions of conjugated azoalkenes
Lemos, A.An overview of the use of 2H-azirines, conjugated nitrosoalkenes and conjugated azoalkenes bearing phosphorus substituents in addition and cycloaddition reactions is presented, focused on strategies for the synthesis of aminophosphonate and aminophosphine oxide derivatives.
Ethyl 2-(Diisopropoxyphosphoryl)-2H-azirine-3-carboxylate: reactions with Nucle...
Lemos, A.; Alves, Maria José ChãoEthyl 2-(diisopropoxyphosphoryl)-2H-azirine-3-carboxylate, the first example of an azirine bearing simultaneously ester and phosphonate groups was generated in situ and reacted with a number of 1,3-dienes. Cycloadducts or their ensuing rearranged products were isolated in moderate yields.
Addition and cycloaddition reactions of Phosphinyl- and Phosphonyl-2H-Azirines,...
Lemos, A.An overview of the use of 2H-azirines, conjugated nitrosoalkenes and conjugated azoalkenes bearing phosphorus substituents in addition and cycloaddition reactions is presented, focused on strategies for the synthesis of aminophosphonate and aminophosphine oxide derivatives.
Ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate : synthesis and reactivity with di...
Alves, Maria José Chão; Fortes, Gil; Lemos, A.; Martins, Cristina I.Ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate, the first example of an 3-heteroamatic 2H-azirine has been prepared. The reaction of ethyl 3-(2-pyridyl)-2H-azirine-2-carboxylate with conjugated 1,3-dienes, under mild conditions and in the absence of Lewis acid catalyst, afforded cycloadducts in good yield and high stereoselectivity.
Intermolecular alkyl radical addition to methyl 2-(2,6-Dichlorophenyl)-2H-aziri...
Lemos, A.; Guimaraes, Emanuel; Fortes, Gil; Alves, Maria José ChãoThe 2H-azirine 1 acts as an effective radical acceptor for secondary and tertiary alkyl iodides mediated by triethylborane. The addition proceeds with high regio- and diastereo-selectivity.
Azabicyclo[3.2.0]heptan-7-ones (carbapenams) from pyrrole
Gilchrist, Thomas L.; Lemos, A.; Ottaway, Carol J.The azabicyclo[3.2.0]heptan-7-ones 4, 10, 16 and 24 have been prepared from pyrrole. The same general approach has been used for all these derivatives; namely, substitution of pyrrole at the 2- and 5-carbon atoms, catalytic hydrogenation to produce pyrrolidine-2-acetic acid derivatives, and cyclisation using tris(1,3-dihydro-2-oxobenzoxazol-3-yl)phosphine oxide 6. The catalytic hydrogenation of 2,5-disubstitute...
Reaction of pyrroles with ethyl 2-nitroso- and 2-azo-propenoates, and with ethy...
Gilchrist, Thomas L.; Lemos, A.The reaction of ethyl 2-nitrosopropenoate 2a with 1 -methylpyrrole, 2.5-dimethylpyrrole and 2.5- diphenylpyrrole has been investigated. In every case the products result from highly regioselective attack at C-2 of the pyrrole by the electrophile. The azopropenoate esters 2b and 2c react similarly with pyrroles, to the extent that even 1 -(triisopropylsilyl)pyrrole is attacked exclusively at the 2-position by th...
Reactions of azoalkenes derived from hydrazones of ethyl bromopyruvate with ele...
Clarke, S; Gilchrist, Thomas L.; Lemos, A.; G. Roberts, TonyThree hydrazones of ethyl bromopyruvate, the dinitrophenylhydrazone 2a, the toluene-4-sulphonylhydrazone 2b and the t-butoxycarbonylhydrazone 2c, have been reacted with a series of nucleophilic alkenes and heterocycles in the presence of sodium carbonate. Azoalkenes 3 are presumed as intermediates and adducts have been isolated. The azoalkenes derived from hydrazones 2a and 2c are found to be useful electrophil...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||