Design, Synthesis and Biological Evaluation of 2‐(2‐Aryl‐morpholino‐4‐yl)ethyl Esters of Indomethacin as Potential Cyclooxygenase‐2 (COX‐2) Inhibitors

A number of novel 2-(2-arylmorpholino-4-yl)ethyl 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-acetate hydrochlorides were synthesized and tested for their cyclooxygenase (COX-1 and COX-2) inhibition properties in vitro. Many of these compounds exhibited moderate to good selective COX-2 inhibition, and subtle structural changes in the substituents on the side chain of the ester moiety altered the inhibitory properties significantly. 2-[2-(4-Butoxyphenyl)morpholino-4-yl]ethyl 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-acetate hydrochloride (1f), showed good selective COX-2 inhibitory activity (Selective index (SI) 182), which is comparative with celecoxib (SI 214), a COX-2 inhibitor of diarylpyrazoles. While 2-[2-(2,4-dichloro-5-fluorophenyl)morpholino-4-yl]ethyl 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-acetate hydrochloride (1g), showed greater selective COX-2 inhibitory activity (SI 358) than celecoxib. Both compounds were identified as compromising derivatives in this class to reduce the side effects generated by nonsteroidal anti-inflammatory drugs (NSAIDs) indomethacin.