Synthesis and aldose reductase inhibitory activity of substituted 2-oxoquinoline-1-acetic acid derivatives.

A number of 2-oxoquinoline-1-alkanoic acids that contain the N-acylglycine fragment found in several known inhibitors of aldose reductase were synthesized and tested in the rat lens assay. All of the target compounds were prepared by alkylation of the appropriate 2-oxoquinoline intermediates with a halo ester, followed by hydrolysis of the intermediate esters. In the rat lens assay, the 1-acetic acid derivatives 9a-e display the highest level of aldose reductase inhibitor activity with IC50 values of 0.45-6.0 microM. Modification of the 1-acetic acid moiety by esterification, substitution of an alpha-methyl group, or insertion of an additional methylene unit results in reduced inhibitory potency. Structure-activity data also suggests that both the benzene and 2-oxopyridine rings of 9a-e contribute substantially toward activity and that inhibitory potency is influenced by aromatic ring substituents.