Synthesis and toxicological properties of some alkyl and aryl 3,4‐methylenedioxyphenyl N,N′‐thio‐bis‐N‐methylcarbamates

A series of asymmetrical thio‐bis‐N‐methylcarbamate derivatives were synthesised by combining 3,4‐methylenedioxyphenyl N‐methylcarbamate with different N‐methylcarbamates. Some of these derivatives combined good insecticidal activity against the housefly with reduced acute oral toxicity to mice. The thio‐bis‐N‐methylcarbamates obtained exhibited a lower anti‐cholinesterase activity than the more toxic of the two carbamate moieties contained in each combination. The weak synergism of piperonyl butoxide on the insecticidal activity of the derivatives suggests the possibility of a self synergism phenomenon caused by the 3,4‐methylenedioxyphenyl group.