Sodium Hydroxide → 2-amino-4,5-dimethylthiophene-3-carboxylic acid

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Reaction Steps

A mixture of 15 parts of ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate and 75 parts by volume of 2N solution of sodium hydroxide in 50 % aqueous ethanol is refluxed for 2.5 hours. After cooling the solution is diluted with 75 parts by volume of water and neutralized with acetic acid under cooling with ice. The resulting precipitate is collected by filtration to give 2-amino-4,5-dimethylthiophene-3-carboxylic acid as crystals. Recrystallization from chloroform with charcoal gives colorless needles melting at 136°-138°C (decomposition).

Provenance & Evidence