Synthesis of heteroaromatic analogs of (2-aryl-1-cyclopentenyl-1-alkylidene)(arylmethyloxy)amine COX-2 inhibitors: effects on the inhibitory activity of the replacement of the cyclopentene central core with pyrazole, thiophene or isoxazole ring

Several heteroaromatic analogues of (2-aryl-1-cyclopentenyl-1-alkylidene)-(arylmethyloxy)amine COX-2 inhibitors, in which the cyclopentene moiety was replaced by pyrazole, thiophene or isoxazole ring, were synthesized, in order to verify the influence of the different nature of the central core on the COX inhibitory properties of these kinds of molecules. Among the compounds tested, only the 3-(p-methylsulfonylphenyl) substituted thiophene derivatives 17 and 22, showed a certain COX-2 inhibitory activity, accompanied by an appreciable COX-2 versus COX-1 selectivity. Only one of the 1-(p-methylsulfonylphenyl)pyrazole compounds (16) displayed a modest inhibitory activity towards both type of isoenzymes, while the pyrazole 1-(p-aminosulfonylphenyl) substituted 12 proved to be significantly active only towards COX-1. All the isoxazole derivatives were inactive on both COX isoforms.