Identification of new 4-(6-oxopyridazin-1-yl)benzenesulfonamides as multi-target anti-inflammatory agents targeting carbonic anhydrase, COX-2 and 5-LOX enzymes: synthesis, biological evaluations and modelling insights.

Multiple inhibitions of CA, COX-2 and 5-LOX enzymes has been recognised as a useful strategy for the development of anti-inflammatory drugs that can avoid the disadvantages of using NSAIDs alone. Here, we report new pyridazine-based sulphonamides (5a-c and 7a-f) as potential multi-target anti-inflammatory candidates. First, the furanone heterocycle in the dual CA/COX-2 inhibitor Polmacoxib was replaced with the pyridazinone one. Then, a hydrophobic tail was appended through benzylation of the 3-hydroxyl group of the pyridazinone scaffold to afford benzyloxy pyridazines 5a-c. Furthermore, the structures were adorned with the polar sulphonate functionality, in pyridazine sulphonates 7a-f, that are expected to be engaged in interactions with the hydrophilic half of the CA binding sites. All of the disclosed pyridazinones were tested for inhibitory activities against 4 hCA isoforms (I, II, IX, and XII), as well as against COX-1/2, and 5-LOX. Furthermore, in vivo anti-inflammatory and analgesic effects of pyridazinones 7a and 7b were examined.