Carboxylic acid derivatives of pyridoxal were developed as potent P2X1 and P2X3 receptor antagonists with modifications of a lead compound, pyridoxal-5′-phosphate-6-azophenyl- 2′, 5′-disulfonate (5b, iso-PPADS). The designing strategies included the modifications of aldehyde, phosphate or sulfonate groups of 5b, which may be interacted with lysine residues of the receptor binding pocket, to weak anionic carboxylic acid groups. The ...
