Insecticidal carbamoyloximes

A review of the salient features of the activity of carbamoyloximes, the newest category of insecticidal and acetylcholinesterase-inhibiting carbamates, shows their marked resemblance to the carbamates of cyclic enols and of phenols. The electronic effect of substituents on anticholinesterase activity is more obvious for the carbamoyloximes than it is for the carbamates of phenols. Alkylthio substituents appear to affect activity directly by increasing the affinity for acetylcholinesterase and indirectly through their potential for sulphoxidation. Although carbamoyloximes as a class are active against all major types of insect pest, individual compounds usually are highly selective. Much of this selectivity is probably the the result of detoxification. Methylenedioxyphenyl derivatives synergise many of these carbamates against the housefly. The rǒle of physical properties in determining penetration, detoxification, synergism, and systemic action is discussed with special reference to ‘Temik’ (2-methyl-2 methylthiopropionaldehyde O-(methylcarbamoyl)oxime) and its oxidation products.