TY - JOUR
T1 - Bentonite clay
T2 - An efficient catalyst for the synthesis of 2-substituted benzimidazoles
AU - Cardozo, Victor A.
AU - Sánchez-Obregón, Rubén
AU - Salgado-Zamora, Héctor
AU - Jiménez-Juárez, Rogelio
N1 - Publisher Copyright:
© 2015 Springer-Verlag Wien.
PY - 2015/8/23
Y1 - 2015/8/23
N2 - 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.
AB - 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.
KW - 4-Chloro-o-phenylenediamine
KW - Aryl aldehyde
KW - Bentonite clay
KW - Benzimidazoles
KW - Heteroaryl aldehyde
KW - o-Phenylenediamine
UR - http://www.scopus.com/inward/record.url?scp=84922692433&partnerID=8YFLogxK
U2 - 10.1007/s00706-015-1423-x
DO - 10.1007/s00706-015-1423-x
M3 - Artículo
SN - 0026-9247
VL - 146
SP - 1335
EP - 1337
JO - Monatshefte fur Chemie
JF - Monatshefte fur Chemie
IS - 8
ER -