Sodium Hydroxide → 7-Ethyl-2-methyl-4-oxo-4,7-dihydrothieno(2,3-b)pyridine-5-carboxylic acid

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Reaction Conditions

Reaction Steps

A mixture of 0.24 part of ethyl 7-ethyl-4,7-dihydro-2-methyl-4-oxothieno(2,3-b)pyridine-5-carboxylate and 3 parts by volume of 2N sodium hydroxide is heated at 90° C for 5 minutes. After cooling the solution is neutralized with acetic acid to give a precipitate which is collected by filtration, whereby 7-ethyl-4,7-dihydro-2-methyl-4-oxothieno(2,3-b)pyridine-5-carboxylic acid is obtained as crystals. Recrystallization from chloroform-ethanol gives colorless prisms melting at 232°-233° C. This product is identical with the product in Example 13.

Provenance & Evidence