A series of conformationally controlled 2-PAM derivatives were prepared fro
m 2-acetylpyridine and 2,3-pyrido[b]cycloalkenones in two steps and their r
eactivities towards parathion poisoned AChE were evaluated. The most planar
2,3-pyrido[b]cyclohexanone oxime methiodide showed an activity comparable
to 2-PAM implying E-syn is that the most active comformation of 2-PAM in th
e biological system.