Bentonite clay: An efficient catalyst for the synthesis of 2-substituted benzimidazoles
Por:
Cardozo V.A., Sánchez-Obregón R., Salgado-Zamora H., Jiménez-Juárez R.
Publicada:
1 ago 2015
Categoría:
Chemistry (miscellaneous)
Resumen:
Benzimidazoles have been reported to have a wide range of biological and therapeutic properties. For this reason a variety of methods for their synthesis has been described, following one of the two general routes: the coupling of o-phenylenediamine and carboxylic acids or their derivatives using a strong acid and high temperature, or a two-step sequence that involves oxidative cyclodehydrogenation of Schiff's bases, obtained by the reaction of o-phenylenediamines and aromatic aldehydes. A simple, efficient, and environmentally friendly procedure for the synthesis of substituted 2- and 2,5(6)-substituted benzimidazoles is herein described. The procedure is carried out by treatment of o-phenylenediamine or 4-chloro-o-phenylenediamine with aryl or heteroaryl aldehydes. Bentonite clay is used as catalyst in dry acetonitrile at room temperature. This procedure has several important advantages, including short reaction times, large-scale preparations, easy isolation of the products, and good to excellent yields. © 2015 Springer-Verlag Wien.
Filiaciones:
Univ Nacl Autonoma Mexico, Inst Quim, Mexico City 04510, DF, Mexico
Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Mexico D.F., 11340, Mexico
Instituto de Química, UNAM, Coyoacán, Mexico D.F., 04510, Mexico
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