FORMYLIERUNGSVERFAHREN FÜR AROMATISCHE ALDEHYDE

摘要

A novel two-step reaction process for preparing 5-substituted-2-methoxybenzaldehyde compounds is disclosed wherein the substituent group is either isopropyl or trifluoromethoxy. The process involves (1) reacting a corresponding 4-substituted phenol compound with dimethyl carbonate in the presence of a tertiary-amine base to form the corresponding 4-substituted anisole compound, and (2) thereafter subjecting the latter intermediate product obtained in the first step to aromatic C-formylation on the ring with hexamethylenetetramine in the presence of trifluoroacetic acid, followed by hydrolysis, to ultimately yield the desired aldehyde compound. The two aromatic aldehyde compounds so obtained, viz., 2-methoxy-5-trifluoromethoxybenzaldehyde and 2-methoxy-5-isopropylbenzaldehyde, are known to be useful as intermediates that specifically lead to (2S,3S)-cis-3-(2-methoxy-5-trifluoromethoxybenzyl)amino-2-phenylpiperidine and (2S,3S)-cis-2-(diphenylmethyl)-N-((2-methoxy-5-isopropylphenyl)methyl)-1-azabicyclo(2.2.2)octane-3-amine, respectively. The latter final products, in turn, are both known to be useful in the field of medicinal chemistry as substance P receptor antagonists.