A Green Approach: Eosin Y-Facilitated Visible Light Preparation of a Functionalized 1,2,3- Triazole Compound

A key goal of contemporary organic chemistry is developing environmentally acceptable, sustainable methods for synthesising nitrogen-containing heterocycles. Because of their broad biological activities and uses in medicinal chemistry, 1,2,3- triazoles have garnered considerable attention among these heterocycles. In this study, we devised a visible-light-induced process for synthesising (4-hexyl-2H-1,2,3-triazole-2-yl) methanol using Eosin Y as an organic photocatalyst. The reaction is a threecomponent coupling of formaldehyde, sodium azide, and terminal alkynes that occurs under visible light at ambient temperature. Eosin Y (5 molparcent) in an H2O/DMSO (1:1) solvent system under blue LED irradiation yields the required triazole derivatives in good yield when reaction parameters are optimised. Control studies validated the crucial roles of visible light and the photocatalyst in the reaction. Without a transition-metal catalyst, the transformation proceeds under mild conditions, demonstrating the protocols environmental friendliness. We propose a viable photoredox process that generates reactive intermediates and activates Eosin Y under visible light. This process offers a straightforward, effective, and environmentally friendly way to create functionalized 1,2,3-triazole derivatives.