Synthesis and enzyme inhibitory activities of some new pyrazole-based heterocyclic compounds

Three tridentate N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)-1-hydroxy-2-aminoethane (2), N,N-bis(3,5-dimethylpyrazol-1-ylmethyl)-cyclohexylamine (3) and 2-[bis(1,5-dimethyl-1H-pyrazol-3-ylmethyl)amino]ethan-1-ol (4) are synthesized and spectroscopically characterized together with 1-hydroxymethyl-3,5-dimethylpyrazole (1). These have been tested in inhibitory activities against various hyperactive enzymes like urease, beta-glucuronidase, phosphodiesterase, alpha-chymotrypsin, acetylcholinesterase and butyrylcholinesterase. Compounds 1, 2 and 3 were found to be selective inhibitors of urease. Compound 4 was found to be selective inhibitor of butyrylcholinesterase. The nature of the junction between pyrazoles cycles determined the activities of these tripods. While the tripods are inactive towards urease or glucuronidase, they turn to be selective towards butyrylcholinesterase.