GB923253A - New thiophosphoric acid esters and pesticidal compositions containing them - Google Patents

Abstract

The invention comprises compounds of the general formula:- <FORM:0923253/IV(a)/1> wherein R1 and R2, which can be the same or different, are methyl, ethyl, or propyl radicals, R3 is phenyl, a phenyl radical having an electronegative substituent (e.g. a halogen atom or nitro group), or a methyl, ethyl or propyl radical which is either unsubstituted or substituted in its a position with the group ZR8 where Z is oxygen or sulphur and R8 is a methyl or ethyl radical, R4, R5 and R6, which can be the same or different are each a hydrogen atom or a methyl radical, R7 is a C1-C4 alkyl radical and X is oxygen or sulphur. They may be obtained by reacting a compound (R1O)(R2O) P(:X)SM wherein M is an alkali metal or ammonium with a compound Y.C(R3)(R4). C(R5)(R6).COOR7 wherein Y is a halogen atom, e.g. chlorine or bromine. The reaction may be carried out in an organic solvent, e.g. methanol or ethanol, acetone, or dioxane and suitable reaction temperatures vary from room temperature to 150 DEG C. Also, compounds in which R6 is a hydrogen atom and X is sulphur may be obtained by reacting a compound of the formula (R1O)(R2O) P(:S)SH with an unsaturated ester of the formula (R3)C(R4)=C(R5).COOR7, wherein R1 to R7 are as defined above. The reaction is preferably carried out in the presence as catalyst, of a small amount of a base, e.g. piperidine or pyridine or an alkali metal hydroxide or carbonate. An antioxidant, e.g. hydroquinone may also be present. The process may be carried out in an inert diluent, e.g. benzene, toluene, methanol or ethanol and most suitable temperatures are from 15 DEG C. to 150 DEG C., especially 50 to 100 DEG C. Several examples are given and the products have pesticidal properties (see Group VI). According to the Provisional Specification the Group R3 may also be an alkyl radical substituted by a dialkylamino or carboxylic ester group or may be a phenyl radical substituted by one or more alkyl or alkoxy radicals.ALSO:A pesticidal composition contains as active ingredient a compound of the general formula <FORM:0923253/VI/1> wherein R1 and R2 which can be the same or different are methyl, ethyl, or propyl radicals, R3 is a phenyl radical, a phenyl radical having an electronegative substituent e.g. a halogen atom or nitro group, or a methyl, ethyl, or propyl radical, which is either unsubstituted or substituted in its a position with the group -ZR8 where Z is an atom of oxygen or sulphur and R8 is a methyl or ethyl radical, R4, R5 and R6 which can be the same or different are each a hydrogen atom or a methyl radical, R7 is an alkyl radical having 1 to 4 carbon atoms and X is an atom of oxygen or sulphur (see Group IV (b)). The composition may be in liquid or solid form and may contain a wetting or dispersing agent. An aqueous dispersion of the active ingredient can be obtained by dissolving it in an organic solvent such as methanol, acetone, tetrahydrofurfuryl alcohol, diacetone alcohol, or b -ethoxyethanol and then dispersing the solution in water, preferably with the aid of a dispersing agent. According to the Provisional Specification the group R3 in the active ingredient may also be an alkyl radical substituted by a dialkylamino or carboxylic ester group or may be a phenyl radical substituted by one or more alkyl or alkoxy radicals.