Process for the production of N-[[2-alkoxy-6-methoxy-5-(trifluoromethyl)-1-naphthalenyl]carbonyl]-N-meth ylglycine esters and intermediates for their production. Said esters are themselves intermediates for the manufacture of compounds which inhibit aldose reductase and are useful for the treatment of diabetic complications.
Process for the production of 2-alkoxy or aryl(lower)alkoxy-6-methoxy-1-naphthalenecarboxaldehyde chemical intermediates by demethylating 2,6-dimethoxy-1-naphthalenecarboxaldehyde with a nucleophilic sulfide reagent at the 2-position and reacting the resulting phenolate salt with an alkylating reagent. Said aldehydes are themselves intermediates for the manufacture of compounds which inhibit aldose reductase and are useful for the treatment of diabetic complications.