Synthesis of derivatives of the keto-pyrrolyl-difluorophenol scaffold: Some structural aspects for aldose reductase inhibitory activity and selectivity

Seven novel ARIs (3a–c, 4a–c and 5) were synthesized with the implementation of an optimized and, partially, selective synthetic procedure, via a Friedel–Crafts acylation reaction. The synthesized ARIs have values of IC₅₀^ALR2 ranging from 0.19 μM (in case of compound 3b) to 2.3 μM (in case of compound 4a), while the values of selectivity index towards ALR1 range from 1 (in case of compound 3b) to 238 (in case of compound 3a). Finally, we found out that the presence of an additional (secondary) aromatic area is not a prerequisite feature for ARI activity.