A process for producing a 1,4-dihydro-4-oxo-quinoline-3-carboxylic acid by reacting an acctophenone with a dialkoxycarbonate to obtain the corresponding .beta.-ketoester, treating the .beta.-ketoester with a trialkylorthoformate in the presence of an acid anhydride followed by treatment with a substituted or unsubstituted amine to obtain the corresponding enaminoketoester, and then reacting the enaminoketoester with a strong base to obtain the corresponding quinoline-3-carboxylic acid ester. The acid ester may then be hydrolyzed, if desired, to obtain the quinoline-3-carboxylic acid. Also disclosed herein are compounds useful as intermediates useful in the production of quinoline-3-carboxylic acid.