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THE INSECTICIDAL ACTIVITY OF PARATHION, ITS ISOMERS AND SOME RELATED COMPOUNDS
Author(s) -
WOODCOCK D.,
STRINGER A.
Publication year - 1951
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1951.tb07792.x
Subject(s) - thiophosphate , parathion , paraoxon , toxicology , medicinal chemistry , organic chemistry , chemistry , biology , nuclear chemistry , pesticide , acetylcholinesterase , ecology , enzyme
Heat treatment of parathion at 140° C. and above resulted in isomerization and then thermal decomposition; the loss of toxicity to Calandra granaria being correlated with a reduction of the thiono‐sulphur content. Similar results were obtained with O:O‐dimethyl‐(4‐nitrophenyl)‐thiophosphate. Paraoxon, O:S‐diethyl‐(4‐nitrophenyl)‐thiophosphate, and O:O‐diethyl‐S‐(4‐nitrophenyl)‐thiophosphate, although all possessing considerable contact activity, were less insecticidal than parathion; O:O‐dimethyl‐(4‐nitrophenyl)‐thiophosphate, on the other hand, was considerably more effective than parathion. O:O‐ bis (2‐chloroethyl)‐O‐(4‐nitrophenyl)‐thiophosphate was considerably less toxic than parathion and appeared to have a different mode of action. Compounds, S‐ethyl‐ bis ‐(4‐nitrophenyl)‐thiophosphate, O‐ethyl‐ bis ‐(4‐nitrophenyl)‐thiophosphate, and triethyl thiophosphate were ineffective as contact insecticides. In the series of compounds examined, replacement of the group P = S by P = O or alteration in size of the groups attached to the central phosphorus atom caused a reduction of insecticidal activity.