Synthesis and selective cyclooxygenase-2 inhibitory activity of a series of novel, nitric oxide donor-containing pyrazoles.

Ramani R Ranatunge, Michael Augustyniak, Upul K Bandarage, Richard A Earl, James L Ellis, David S Garvey, David R Janero, L Gordon Letts, Allison M Martino, Madhavi G Murty, Stewart K Richardson, Joseph D Schroeder, Matthew J Shumway, S William Tam, A Mark Trocha, Delano V Young

Index: J. Med. Chem. 47 , 2180-2193, (2004)

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Abstract

The synthesis of a series of novel pyrazoles containing a nitrate (ONO(2)) moiety as a nitric oxide (NO)-donor functionality is reported. Their COX-1 and COX-2 inhibitory activities in human whole blood are profiled. Our data demonstrate that pyrazole ring substituents play an important role in COX-2 selective inhibition, such that a cycloalkyl pyrazole (6b) was found to be a potent and selective COX-2 inhibitor. Other modifications at the 3 position of the central pyrazole ring (17b, 23b, 26b-I) enhanced COX-2 inhibitory potency. Among the pyrazoles synthesized, the oxime (23b) was identified as the most potent COX-2 selective inhibitor. Accordingly, 23b was profiled pharmacologically in the rat after oral administration and shown to possess potent antiinflammatory activity in the carrageenan-induced air-pouch model and less gastric toxicity than a standard COX-2 inhibitor when administered with background aspirin treatment. We suggest that the enhanced gastric tolerance of an NO-donor COX-2 selective inhibitor has the potential to augment the clinical profile of this drug class.