Development and Scale-Up of a Novel Photochemical C-N Oxidative Coupling

A visible light promoted C-N-coupling of a functionalized pyridazinone with veratrole was developed to forge the central C-N bond of an agrochemical intermediate. Dosing aqueous NaOCl and 4% O-2 in N-2 under blue light irradiation (460 nm) was key to promote the desired transformation while generating benign wastes. Mechanistic studies suggest the formation of a N-chloro species that undergoes selective coupling via a radical pathway induced by the combination of light and oxygen. Further development led to an optimized semi-batch process, which was successfully scaled up to an initial 20 L and then 1.2 m(3).

Automated summary

A visible light-promoted C-N coupling method was developed for forging the central C-N bond of an agrochemical intermediate. Mechanistic studies showed that selective coupling was achieved through a radical pathway induced by the combination of light and oxygen, leading to successful scale-up to initial 20L and then 1.2m³.