4-Ethylbenzoic Acid → Methyl 3-methyl-1H-indole-6-carboxylate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Methyl 4-ethyl-3-nitrobenzoate (5.0 g), which had been prepared through nitration followed by methyl-esterification of 4-ethylbenzoic acid, is dissolved in N,N-dimethylformamide (50 ml), to which is added N,N-dimethylformamide dimethyl acetal (8.45 g), and stirred under heat at 130° C. for 3 hours. The reaction mixture is concentrated under reduced pressure, and the resulting red oily residue is dissolved in methanol (50 ml), to which is added palladium-carbon (5%, 0.400 g), and stirred in a hydrogen atmosphere at room temperature for 2.5 hours. Then, this is further stirred at 50° C. for 2 hours and thereafter at room temperature for 3 days. The catalyst is removed through filtration, and the filtrate is concentrated under reduced pressure. The resulting residue is recrystallized from t-butyl methyl ether to obtain a pale yellow crystal of the intended product (2.4 g).

Herkunft & Nachweise