1‐Ethyl‐1,4‐dihydro‐4‐oxo‐7‐(pyridinyl)‐3‐quinolinecarboxylic acids. II. Synthesis

Abstract

Abstract The preparation of a variety of 1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐pyridinyl‐3‐quinolinecarboxylic acids with a range of substituents on the pyridine ring is described. Starting with the appropriately substituted aniline and using the first two steps of the Gould‐Jacobs quinoline synthesis the 7‐pyridinyl‐3‐quinolinecarboxylates can be obtained. Ethylation at the 1‐position and hydrolysis of the ester group gives the desired acid products. These compounds have significant antibacterial activity: 1‐ethyl‐1,4‐dihydro‐4‐oxo‐7‐(4‐pyridinyl)‐3‐quinolinecarboxylic acid is now in clinical study and 7‐(2,6‐dimethyl‐4‐pyridinyl)‐1‐ethyl‐1,4‐dihydro‐4‐oxo‐3‐quinolinecarboxylic acid is under advanced evaluation.