LAUSR

ABSTRACT The potential of glutathione as a catalyst for carbon–oxygen ring cyclization was investigated experimentally as well as computationally. The glutathione molecules were immobilized on superparamagnetic iron-oxide nanoparticle so as to improve the efficiency of the catalyst and to augment magnetically aided recyclability. Ultrasound was also exploited for thorough dispersion of the nanoparticles in the aqueous medium so that contact between the catalyst and the reactants are enhanced. This nano-organocatalyst was synthesized and characterized by the following analytical techniques: TEM, scanning electron microscope, EDS, powder X-ray diffraction, vibrating sample magnetometry, FTIR, TGA, DTA. Its catalytic prowess in the synthesis of several indolyl chromenes, pyrrolyl chromenes, and indoloxanthenes were meticulously investigated. The synthetic protocol was found to be efficient, economical, and environment benign. Quantum chemical studies were performed to study the effect of the catalyst on C–O ring cyclization using Gaussian program viz. B3LYP. GRAPHICAL ABSTRACT