Photoreduction of Nitro (Hetero)arenes to (Hetero)arylhydroxylamines by isoPropanol in Flow: Application to the Synthesis of Paracetamol.

The photoreduction of substituted nitro (hetero)arenes by iPrOH has been achieved in batch and continuous flow chemistry. Good yields of N-(hetero)arylhydroxylamines were obtained when nitrobenzene was substituted by electron-withdrawing groups. The reaction is chemoselective as nitriles, esters, carboxylic acids, ketones, and halides are not reduced. The application of the photoreduction of nitrobenzene to the synthesis of paracetamol was achieved by the acetylation of N-phenylhydroxylamine followed by an original 1,5-rearrangement.