RESUMO
Catalytic enantioselective 1,3-dipolar cycloaddition between imino esters and electrophilic alkenes, employing chiral metal complexes derived from copper(I) and silver(I) salts and (S)-DM- or (S)-DTBM-Segphos as ligands produces diastereodivergently exo- or endo-cycloadducts, respectively. The effect of the functional group of the dipolarophile and the fine tuning of the catalyst plays an important role in promoting reverse diastereoselectivities. The origins of experimentally observed enantioselectivity and diastereoselectivity data, as well as the origin of the observed switched endo/exo ratios, are also explained by means of density functional theory calculations.
RESUMO
The synthesis of 3,3-disubstituted N-methyloxindoles, starting from 3-acetyl-2-hydroxy-1-methyloxindole employing a sequential one-pot synthesis, is studied. The process involves a first alkylation in the presence of 1 equiv. of both organic halide and Triton B and the second one employs another 1.5 equiv. of each in moderate to high yields. This procedure is compared with the results obtained from the direct dialkylation of N-methyloxindole. The metathesis of one of the corresponding diallylated product was also studied obtaining the spiranic oxindole. All these methodologies are directed towards the access to anticancer agents and natural biologically active products.
Assuntos
Antineoplásicos/síntese química , Produtos Biológicos/síntese química , Indóis/síntese química , Acilação , Alquilação , Antineoplásicos/química , Produtos Biológicos/química , Cromatografia Gasosa , Indóis/química , Estrutura Molecular , OxindóisRESUMO
Usando seis diferentes probes de cromossomo X, estimou-se a freqüência de polimorfismo de comprimento de fragmento de restriçäo (RFLP) com endonucleases de restriçäo em pessoas näo parentes, em uma populaçäo espanhola de Valência. As freqüências de alelos foram semelhantes às de outras populaçöes européias, em particular francesas e turcas. Um alto grau de polimorfismo foi encontrado para todos os marcadores, sendo que a freqüência do alelo raro variou de 0,484 a 0,357 e um alto nível de heterozigose dos marcadores L1.28, 754, OTC e p58.1 foi encontrado nesta populaçäo, confirmando sua utilidade para a diagnose.