Sulfuric Acid → Ethyl 2,3-dimethyl-7-bromo-5-benzofurancarboxylate

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Reaction Steps

Analogously to Example (17b), using 315.2 g (1 mol) of ethyl 3-bromo-4-(1-methyl-2-oxopropoxy)-benzoate and 400 g of 94% sulfuric acid, first with ice-cooling, then at room temperature for one hour and thereafter at 50° for 8 hours, ethyl 2,3-dimethyl-7-bromo-5-benzofurancarboxylate of melting point 110°-111° is obtained by recrystallising the neutral portion from hot ethanol, and 2,3-dimethyl-7-bromo-5-benzofuranylcarboxylic acid of melting point 249°-251° is obtained by recrystallising the acid portion from hot ethanol.

Provenance & Evidence