Synthesis and anticholinesterasic activity of some .alpha.-thiosubstituted O-(methylcarbamoyl)oximes

A series of six oxime N-methylcarbamates, C6H5C(R)=NOCONHCH3[ R = SCH3, CH2SCH3,( 2)-an d (E)-CH(CH),)SCH,, C(CH3)2SCH3C, (CH3),], analogues of commercial compounds such as aldicarb, butocarboxim, methomyl, and thiofanox, was synthesized for potential anticholinesterasic activity. NMR, IR, and UV were used to assign the configurations. The kinetic study of the inhibition of acetylcholinesterase from bovine erythrocyte and the determination of the dissociation constant Kd and of the carbamylation rate constant k2 allowed discussion of the importance of the number of methyl groups on the carbon a to the iminic group. The insertion of the phenyl group generally did not improve the activity but yielded compounds, one isomer of which had a potential activity close to that of the commercial compounds