Application of biological-based nano catalysts in the preparation of arylbispyranylmethanes

The catalytic active species with small metal-free organic molecules entitled ―organocatalysts‖ found their key roles as promoter and established highly dynamic area in the academic and also industrial sectors in the past few years and the organocatalysis has grown dramatically [1]. A striking advantage of organocatalysts is their high surface to volume ratio which can intensifythe possibility of the interaction between reactants and catalyst and lead to multiplying the catalytic performance of the applied organocatalysts [2,3]. Herein, the utilization of 2-carbamoylhydrazine-1-sulfonic acid and carbamoylsulfamic acid were described as biological-based nanoorganocatalystswith urea moiety for the synthesis of arylbispyranylmethane derivatives under mild and eco-friendly conditions. A good range of aromatic aldehydes were treated with 4-hydroxy-6-methyl-2-pyrone to give arylbispyranylmethane derivatives through a tandem Knoevenagel condensation and Michael addition procedure in relatively short reaction times with high yields. The presented protocols have merits like the eco-friendly nature, high efficiency, simple operational procedures and benign reaction conditions(Figure 1).