Nanoporous TiO2 containing an ionic liquid bridge as an efficient and reusable catalyst for the synthesis of N,N′-diarylformamidines, benzoxazoles, benzothiazoles and benzimidazolesElectronic supplementary information (ESI) available: FT-IR, 1H NMR and 13C NMR of the new products. See DOI: 10.1039/c8nj00171e

In this work, a green and efficient procedure is reported for the preparation of N , N' -diarylformamidines, benzoxazoles, benzothiazoles, and benzimidazoles using nanoporous TiO 2 containing an ionic liquid bridge. This reagent is prepared via the modification of nanoporous TiO 2 with bis-3-(trimethoxysilylpropyl)-ammonium hydrogen sulfate (TiO 2 -[bip]-NH 2 + HSO 4 − ). The procedure gave the products in excellent yields in very short reaction times under solvent-free conditions. The reusability of the catalyst is the other important feature of the reported method. Nanoporous TiO 2 modified with an ionic liquid was used for efficient coupling of amines, 1,2-phenylene diamines, 2-aminophenol and 2-aminothiophenol with orthoesters.