[Bmim]5[PNiW11O39]·3H2O an organic–inorganic hybrid as catalyst for one-pot pseudo-five-component synthesis of tetrazolyldiazepines

In this research, two heterogeneous organic–inorganic hybrid catalysts, [bmim]3[PW12O40]·3H2O and [bmim]5[PNiW11O39]·3H2O, have been prepared. The catalysts were fully characterized by several techniques such as elemental analyses, Fourier transform infrared spectroscopy, thermo-gravimetric analysis, scanning electron microscope and energy-dispersive X-ray analysis. Next, the hybrid catalysts have been used for the synthesis of functionalized diazepines containing tetrazole ring. Tetrazolyl-1H-spiro[benzo[b]cyclopenta[e][1,4] diazepines products were obtained in excellent yields and mild experimental conditions using [bmim]5[PNiW11O39]·3H2O as catalyst. This process was carried out via a one-pot, pseudo-five-component condensation reaction by means of a 1,2-diamine, isocyanide, TMSN3 and two molecules of a linear or cyclic ketone in methanol, at ambient temperature.