Investigations on Acid Base Mediated Synthesis of Organophosphonates Phosphates and Their Applications

Abstract

The thesis entitled Investigations on Acid / Base Mediated Synthesis of Organophosphonates / Phosphates and Their Applications deals with the synthesis and applications of biologically and synthetically important organophosphorus compounds using straightforward synthetic methodologies. We have divided this thesis in four chapters along with a general introduction on organophosphorus chemistry. newlineGeneral introduction describes the origin of organophosphorus chemistry and its importance in numerous research fields such as chemicals, materials, biological and pharmaceutical sciences. We have also discussed some highly relevant and renowned name reactions. newlineThe first chapter of thesis describes a FeCl3-mediated regio-and stereo selective Friedel-Crafts-type arylation of selected and#945;-hydroxy phosphonates with unactivated arenes, in which the unstable allylphosphonate cations generated are stabilized by extended conjugation. This method provides a simple, efficient and economical approach to highly demanding stereo selective and#947;-aryl-substituted vinylphosphonates and dialkyl (diarylmethyl)phosphonates with good regioselectivity. These reactions proceed under mild conditions in the absence of any additional solvent. Synthesis of and#945;-halophosphonates can be easily carried out at room temperature by the treatment of HX (HCl, HBr) with specific and#945;-hydroxyphosphonates. newlineThe second chapter of thesis briefly describes an operationally simple synthetic method to access (±)-and#945;-aryl/methylsulfonamidomethylphosphonates and new (±)-and#947;-aryl/methyl sulfonamidomethylvinylphosphonates through straightforward reactions of (±)-and#945;-hydroxyphosphonates with sulfonamides in the presence of triflic acid (TfOH) at room temperature in a vessel open to air. For and#947;-dimethylallylhydroxyphosphonate, the (E)-1,3-butadienylphosphonate was formed quantitatively using TfOH while FeCl3 afforded the expected product in moderate yield unpredictably.