Synthesis of new compounds bearing methyl sulfonyl pharmacophore as selective COX-2 inhibitor

Cyclooxygenase, also known as prostaglandin H2 synthase (PGH2), is one of the most important enzymes in pharmacology because inhibition of COX is the mechanism of action of most nonsteroidal anti-inflammatory drugs. In this study, ten thiazole derivative compounds had synthesized. The analysis of the obtained compounds was performed by ¹H NMR and ¹³C NMR methods. By this method, the obtained compounds could be elucidated. The inhibitory effect of the obtained compounds on cyclooxygenase (COX) enzymes was investigated. The encoded compounds 5a, 5b, and 5c were found to be the most potent compared to the reference compounds ibuprofen (IC₅₀ = 5.589 ± 0.278 μM), celecoxib (IC₅₀ = 0.132 ± 0.004 μM), and nimesulide (IC₅₀ = 1.692 ± 0.077 μM)against COX-2 isoenzyme. The inhibitory activity of 5a, 5b, and 5c is approximate, but the 5a derivative proved to be the most active in the series with an IC₅₀ value of 0.180 ± 0.002 μM. The most potent COXs inhibitor was 5a, which was further investigated for its potential binding mode by a molecular docking study. Compound 5a was found to be localized at the active site of the enzyme, like celecoxib, which has a remarkable effect on COXs enzymes.