(Ortho)-hydroxy-aromatic aldehyde and ketone prepn. - by oxidation of corresp. benzofuran with molecular oxygen opt. with a catalyst

摘要

Prepn. of o-hydroxy aromatic aldehydes and ketones of formula (I) is by oxidation of a benzafaran with molecular oxygen, opt. in the presence of catalyst, followed if necessary by decomposition of the oxidation prod. by heating or reaction with water. In the formulae R1, R2 independently H or opt. substd. alkyl or aryl R3-6 are independently H, halo, nitro or opt. substd. alkyl, aralkyl or aryl. R3 and R4 or R4 and R5 or R5 and R6 together form a carbocyclic ring. (I) are intermediates for the preparation of dyes, medicaments and plant protection agents. Process gives good yields of (I), using simple appts. and is suitable for industrial scale production as a batch or continuous process.