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vol.47 issue4ESTUDIO DE REDUCCIÓN FOTOCATALIZADA DE CROMO HEXAVALENTETRIBROMOFENOL EMPLEADO EN ASERRADEROS: METODOS DE ANALISIS, CARACTERISTICAS FISICO-QUIMICAS Y PRESENCIA EN COMPONENTES AMBIENTALES author indexsubject indexarticles search
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Boletín de la Sociedad Chilena de Química

Print version ISSN 0366-1644

Abstract

SOBARZO-SANCHEZ, Eduardo  and  GOMEZ-JERIA, Juan S.. ESTUDIO TEÓRICO DE LA REGIOSELECTIVIDAD DE LA BOLDINA EN REACCIONES DE SUSTITUCIÓN AROMÁTICA. Bol. Soc. Chil. Quím. [online]. 2002, vol.47, n.4, pp. 477-484. ISSN 0366-1644.  http://dx.doi.org/10.4067/S0366-16442002000400019.

The nitrosation of boldine with nitrous acid in acetic acid and its halogenation with molecular bromine or N-halosuccinimides (halo = Cl, Br, I) in acetic or trifluoroacetic acid exhibit different regioselectivities. Thus, we found that experimentally boldine proceed with Br2 and N-halosuccinimide affording mono-substituted products in C-3 being attributable to the formation of an electron transfer mechanism (ET) while its nitrosation reaction should proceed by electron transfer within an electron donor-acceptor (EDA) complex that precedes the aromatic substitution step. The regiochemistry of the aromatic substitution is explained by Wheland complex and using reactivity descriptors such as electrophilic and free radical superdelocalizabilites.

Keywords : boldine; nitrosation; halogenation; aromatic substitution; donor-acceptor (EDA) complex; electron transfer mechanism (ET).

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