Reactivity of the insecticide fenitrothion toward O and N nucleophiles.
The reactivity of Fenitrothion (1) toward several O- and N-based nucleophiles, including ambident and alpha-nucleophiles, was investigated in basic media at 25 degrees C in water containing 2% 1,4-dioxane. In the reactions with HO(-) and HOO(-) quantitative formation of 3-methyl-4-nitrophenoxide (2) was observed indicating a S(N)2(P) pathway. In the reactions with NH(2)OH, NH(2)O(-), and BuNH(2), demethylfenitrothion (4) was formed along with 2, indicating competition between the S(N)2(P) and S(N)2(C) pathways; no evidence of a S(N)Ar pathway was observed in any case. The observed rate constants were dissected into the values corresponding to the S(N)2(P) and S(N)2(C) pathways. The yield of 4 depends on the nucleophile and on the pH of the reaction, being the main product in the case of BuNH(2). With HOO(-), NH(2)OH, and NH(2)O(-) a significant alpha-effect was observed, confirming the participation of the nucleophile in the rate-limiting step of the reaction.
Rougier
Natalia M
NM
Instituto de Investigaciones en Fisicoquímica de Cordoba (INFIQC), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Medina Allende y Haya de la Torre, Argentina.
Vico
Raquel V
RV
de Rossi
Rita H
RH
Buján
Elba I
EI
D002082:Butylamines / Q000737:chemistry*; D005278:Fenitrothion / Q000737:chemistry*; D006834:Hydrazines / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D019811:Hydroxylamine / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D002082:Butylamines; D006834:Hydrazines; D007306:Insecticides; D014867:Water; C029424:hydrazine; D019811:Hydroxylamine; D006861:Hydrogen Peroxide; C032462:n-butylamine; D005278:Fenitrothion