PURPOSE: To prepare the title compounds which are intermediates of medicines or raw materials of perfumes, in high yield, by oxidizing benzyl alcohols having alkoxy, etc., with oxygen in dimethyl sulfoxide or N,N-dimethyl-formamide using a vanadium catalyst.
CONSTITUTION: Aromatic aldehydes of formula III and IV (e.g. 3,4-methoxybenzaldehyde, 3,4-methylenedioxybenzaldehyde, etc.) are prepared by oxidizing benzyl alcohols of formula I (R1 is lower alkoxy; R2 is H or lower alkoxy; n is 1 or 2) with a gas containing molecular oxygen (e.g. pure oxygen or air) in dimethyl sulfoxide or N,N-dimethylformamide using a vanadium catalyst. The vanadium catalyst is, e.g. vanadium pentoxide, ammonium metavanadate, vanadyl sulfate, etc. Oxidation temperature is 100W180°C, especially 120W150°C.
INOUE TERUHIKO
AMIYA SHINJI
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