Executive Summary : | This project aims at the development of reagentless photochemical and mechaochemical pathways for the synthesis of heterocycles. The visible-light-induced photochemical processes offer many stimulating routes for various photochemical reactions because it offers (1) different mechanism from thermal and catalytic pathways that enhances the substrate scope which was otherwise difficult to get, (2) excitation of the substrates via excited state mechanism which evades the use of hazardous reagents and pathways; and (3) considerable expansion to scope of the reaction protocols and to available substrates for the photochemical reactions. The proposed protocol is confined at identifying new suitable experimental setups involving concentrated solar irradiations (CSR) using Fresnel lens and visible light mediated approaches using artificial light sources which can be employed in for various photochemical transformations through electron transfer and energy transfer routes. Concentrated solar irradiation provides a synergistic photo-thermal effect which can be strategically employed for the synthesis of heterocyclic compounds through different possible mechanistic pathways. The protocols and procedures will be optimized and generalized under different visible light irradiations using different light sources (like white light, blue light and solar radiation) and different solvents using various substrates and reagents. These pathways will then be studied for various possible organic transformations by giving systematic variations of the suitable substituents. The toolbox of the photochemistry will then be tested on a variety of other possible reactions for the synthesis of different biologically important heterocyclic compounds involving in situ oxidation of primary alcohols using molecular oxygen. The another approach in the exploration of atom economical greener protocols with easily accessible final-products without any additional extraction or chromatographic procedures is mechano-chemical protocol which is among the significant reagentless methodologies in organic chemistry. These strategic organic transformations can be extensively utilized because of their high efficiency, atom economy and environment friendly nature. It is believed that this project is based upon the sound ideas originated from the past experience and recent literature data on the visible light mediated photocatalyzed transformations. |