SYNTHESIS AND PESTICIDAL ACTIVITIES OF N-PHOSPHINOYL HETEROCYCLES

Novel N-phosphinoyl heterocycles were synthesized by the reaction of a heterocycle against a phosphorochloridate in the presence of the stro ng base (n-BuLi or NaH). Studies on the structure-activity relationshi ps were carried out as to acaricidal, aphicidal and nematicidal activi ties, respectively. With respect to the heterocyclic portion, the acid ity (pKa) of the parent heterocycles seems to control the pesticidal a ctivities. It is also suggested that the unsymmetrical alkoxy(alkylthi o)phosphinoyl structures with the proper length of alkyl groups are cr ucial to the high pesticidal activities. The effect of the chiral phos phorus atom was investigated as to (sec-butylthio)phosphinoyl]-1,3-thi azolidin-2-one. The levorotatory (-) isomer was shown to be more activ e against various pests.