A method of treating a disease associated with the inhibition of butyrylcholinesterase enzyme, the method comprising administering to a subject in need thereof an effective amount of 4-aminoantipyrine derivative selected from the group consisting of 4-(bis(3-chlorobenzyl) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, 4-(bis(2-chlorobenzyl) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, 4-(bis(3-iodobenzyl) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, 4-(bis(4-iodobenzyl) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, 4-(bis(2-bromobenzyl) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, 4-(bis(4-bromobenzyl) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, and 4-(bis(3-bromobenzyl) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one and a pharmaceutically acceptable salt thereof as inhibitors of butyrylcholinesterase enzyme.