Diethyl ethoxymalonate

Although there is versatility in the synthetic methodologies of each individual quinolone antibacterial, two different methods are utilized to synthesize the basic skeleton of l,4-dihydro-4-oxoquinoline-3-carboxylic acid. The first method is based on the Gould-Jacobs reaction [9] using appropriately substituted aniline derivatives and diethyl ethoxymalonate, which results in the formation of the intermediate anilinomethylenemalonate. Further thermal cyclization of this intermediate followed by hydrolysis gives rise to the targeted l,4-dihydro-4-oxoquinoline-3-carboxylic acid, according to Scheme 1. 

Synthesis of 4-hydroxyquinolines from anilines and diethyl ethoxymalonate via cyclization of the intermediate anilinomethylenemalonate followed by hydrolysis and decarboxylation ... 

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