Abstract
We describe here a simple method for the synthesis of several substituted benzimidazoles using niobic acid Nb2O5.5H2O as heterogeneous catalyst and under solvent-free conditions. This new protocol is general and a range of aromatic and aliphatic aldehydes were condensed with o-phenylenediamine furnishing the corresponding 1,2-disubstituted benzimidazoles selectively in good yields. The catalyst was reused up four times giving the respective products in good yields but with a little decreasing in the selectivity.
Keywords: Aldehydes, atom-economic, benzimidazoles catalysis, condensation, green chemistry, heterogeneous, heterocycles, heterocycles, niobic acid, niobium, nitrogen compounds, phenylenediamine, solid catalyst.
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