Covalent Modification of Organo-Functionalized Graphene Oxide and its Scope as Catalyst for One-Pot Pyrazolo-Pyranopyrimidine Derivatives.

The surface of graphene oxide (GO) was modified using [3-(2-aminoethylamino)propyl]trimethoxysilane (diamine), which exhibited excellent catalytic activity for one-pot multicomponent reactions. The newly synthesized material was fully characterized by various instrumental techniques including Fourier-transfer infrared (FTIR) and Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The instrumental analysis confirmed the successful grafting of organic amine functional groups onto the graphene oxide surface. The diamine-functionalized GO proved to be an excellent catalyst for the synthesis of pyrazolo-pyranopyrimidine derivatives with 93 % yield and high selectivity. The catalytic activity almost remained unaltered up to three cycles. The newly synthesized pyrazolo-pyranopyrimidine derivatives have potential use as scaffolds in designing new pharmaceutical products.