Synthesis and cyclooxygenase inhibition of various (aryl-1,2,3-triazole-1-yl)-methanesulfonylphenyl derivatives


Synthesis and cyclooxygenase inhibition of various (aryl-1,2,3-triazole-1-yl)-methanesulfonylphenyl derivatives

Wuest, F.; Tang, X.; Knieß, T.; Pietzsch, J.; Suresh, M.

A series of 1,4- and 1,5-diaryl substituted 1,2,3-triazoles was synthesized by either Cu(I)-catalyzed or Ru(II)-catalyzed 1,3-dipolar cycloaddition reactions between 1-azido-4-methane-sulfonylbenzene 9 and a panel of various para-substituted phenyl acetylenes (4-H, 4-Me, 4-OMe, 4-NMe2, 4-Cl, 4-F). All compounds were used in in vitro cyclooxygenase (COX) assays to determine the combined electronic and steric effects upon COX-1 and COX-2 inhibitory potency and selectivity. Structure-activity relationship studies showed that compounds having a vicinal diaryl substitution pattern showed more potent COX-2 inhibition (IC50 = 0.03–0.36 µM) compared to their corresponding 1,3-diaryl-substituted counterparts (IC50 = 0.15 to >10.0 µM). In both series, compounds possessing an electron-withdrawing group (Cl and F) at the para-position of one of the aryl rings displayed higher COX-2 inhibition potency and selectivity as determined for compounds containing electron-donating groups (Me, OMe, NMe2). The obtained data show, that the central carbocyclic or heterocyclic ring system as found in many COX-2 inhibitors can be replaced by a central 1,2,3-triazole unit without losing COX-2 inhibition potency and selectivity. The high COX-2 inhibition potency of some 1,2,3-triazoles having a vicinal diaryl substitution pattern along with their ease in synthesis through versatile Ru(II)-catalyzed click chemistry make this class of compounds interesting candidates for further design and synthesis of highly selective and potent COX-2 inhibitors.

Keywords: Click chemistry; Cyclooxygenase-1 and -2 inhibitors; Triazoles

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