Periodic mesoporous organosilica with ionic-liquid framework supported manganese: an efficient and recyclable nanocatalyst for the unsymmetric Hantzsch reaction

An efficient approach for the green and rapid synthesis of biologically active substituted polyhydroquinoline derivatives via unsymmetric Hantzsch reaction using an ionic liquid based periodic mesoporous organosilica supported manganese (Mn@PMO-IL) catalyst under solvent-free conditions is described. This catalyst showed high reactivity and selectivity for the preparation of a set of different derivatives of polyhydroquinolines under moderate reaction conditions and short times. Moreover, the catalyst was also recovered and reused several times without important decrease in reactivity and yields. The nitrogen adsorption-desorption and transmission electron microscopy of the recovered catalyst significantly proved the high stability and durability of the catalyst under applied reaction conditions. Furthermore, compared to the classical methodologies, this method consistently illustrated the advantages of short reaction times, low catalyst loading, high yields, easy separation and purification of the products, and high recoverability and reusability of the catalyst.