Analogue-based design, synthesis and docking of non-steroidal anti-inflammatory agents. Part 2: methyl sulfanyl/methyl sulfonyl substituted 2,3-diaryl-2,3-dihydro-1H-quinazolin-4-ones.

A series of methyl sulfanyl/methyl sufonyl substituted 2,3-diaryl-2,3-dihydro-1H-quinazolin-4-one were designed using analogue-based design, scaffold hopping and shape similarity matching. The designed compounds were synthesized in 2-3 steps with simple chemistry and screened by ovine cyclooxygenases (COXs) inhibitory assay and carrageenan-induced rat paw edema assay. Among the screened compounds, two compounds exhibited 100% cyclooxygenase-2 (COX-2) inhibitory potency without showing cycloxygenase-1 (COX-1) inhibition at 20 μM. The compounds also showed promising in vivo anti-inflammatory potential. A structure-activity relationship within the dataset was established by correlating the effect of aromatic ring substituent constants, structural variables and physico-chemical descriptors with in vivo anti-inflammatory activity. Molecular docking studies were also performed on the title compounds to study the binding interactions to COX-2 active site residues. The experimentally determined COX-2 inhibitory activity was found moderately correlating with binding modes predicted for compounds by Glide XP dock scoring function. The 2,3-diaryl-2,3-dihydro-1H-quinazolin-4-one pharmacophore reported herein should be a new lead for further development of novel non-steroidal anti-inflammatory agents.