Carbazole-based photocatalyst (4CzIPN) for novel donor–acceptor (D–A) fluorophore-catalyzed visible-light-induced photosynthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones via a proton-coupled electron transfer (PCET) process

Based on the Biginelli reaction of β-ketoesters, arylaldehydes, and urea/thiourea, we created a green radical synthesis procedure for 3,4-dihydropyrimidin-2-(1H)-ones/thiones. A PCET (proton-coupled electron transfer) photocatalyst was used in an ethanol solution in an air environment and at room temperature and visible light to provide a renewable energy source. In this study, we seek to create a novel donor–acceptor (D–A) fluorophore that is affordable and widely available. The carbazole-based photocatalyst (4CzIPN), in addition to its time-saving capabilities and simplicity of use, exhibits excellent yields, is energy-efficient, and is ecologically friendly. This makes it possible to track the evolution of environmental and chemical factors throughout time. To determine the turnover number (TON) and turnover frequency (TOF) of 3,4-dihydropyrimidin-2-(1H)-ones/thiones, a study was done. Gram-scale cyclization demonstrates that it may be used in industry effectively.