Process for the production of substituted benzaldehydes

摘要

A process for the production of benzaldehydes which are substituted in the ortho-position by an electrophilic group R, which comprises brominating an ortho-substituted compound of the formula I (I) in which R represents the nitro group, the cyano group, an alkoxy group of 1 to 8 carbon atoms or a halogen atom, under irradiation with visible light in an inert solvent, to give the bromide of the formula II (II) converting the resulting bromide by treatment with an alkali bromide in an inert solvent into a styrene compound of the formula III (III) and ozonising this latter compound in an inert solvent to give the compound of the formula IV (IV)