Patent GB-795340-A (GB)
Title: New insecticidal esters of dithiophosphoric acid
IPC: C07F9/165
Filed: 1954-10-07
Abstract: The invention comprises dithiophosphoric acid esters of the general formula: (R1O)(R2O)P(S).SCHXCH2SR3 wherein R1 and R2 are aliphatic hydrocarbon radicals containing not more than four carbon atoms, R3 is a hydrocarbon radical and X is hydrogen or an organic substituent free from a sulphur atom.  They may be obtained (a) by reacting a compound of the formula (R1O) (R2O)P(S)X, with a compound of the formula R3SCH2CHXX2 wherein X1 is a halogen atom, X2 is a radical S-cation and R1, R2, R3 and X are as defined above; or (b) by reacting a compound of the formula (R1O)(R2O)P(S)X3 with a compound of the formula R3SCH2CHX.X4 wherein X4 is a halogen atom, X3 is a radical S-cation and R1, R2, R3 and X are so defined above.  Suitable compounds for use in method (a) are the chloride or bromide of the dimethyl or diethyl ester of thiophosphoric acid and the sodium mercaptide of 2-mercaptoethyl ethyl sulphide and suitable compounds for method (b) are the alkali metal or ammonium salts of the dimethyl or diethyl ester of dithiophosphoric acid and 2-chloroethyl ethyl sulphide, 2-chloroethyl-benzyl sulphide, ethyl-2-chloropropyl sulphide, ethyl - [3 - methoxy - (or ethoxy -) - 2-chloropropyl] sulphide and tert. butyl-(3-methoxy-2-chloropropyl) sulphide.  The reactions may be carried out in the presence of a solvent such as acetone, benzene, toluene, xylene or water and advantageously at between 50 DEG  and 150 DEG  C.  Examples are given for the production of compounds in which X is hydrogen, R1 and R2 are ethyl and R3 is C2H5 and -CH2-CH = CH2 respectively; X is hydrogen, R1 and R2 are methyl and R3 is C2H5; R1 and R2 are methyl, X is CH3 and R is C2H5; R1 and R2 are ethyl, R3 is C2H5 and X is CH3, -CH2-O-C2H5 and CH2-O-CH3 respectively; R1 and R2 are methyl, R3 is C2H5 and X is CH2.O.C2H5 and CH2-O-CH3 respectively; and in which X is CH2-O-CH3, R3 is -C(CH3)3 and R1 and R2 are methyl.  The products are stated to be valuable pesticides (see Group VI).  Specification 767,950 is referred to.ALSO:An insecticidal composition comprises a dithiophosphoric acid ester of the general formula: (R1O)(R2O)P(S)CHXCH2SR3 in which R1 and R2 are aliphatic hydrocarbon radicals containing not more than 4 carbon atoms, R3 is a hydrocarbon radical, and X is hydrogen or an organic substituent free from a sulphur atom (see Group IV (b)) together with an emulsifying agent and/or an inorganic water-insoluble powdered carrier.  The composition may also include an organic solvent such as a mono- or polyhydric alcohol, aromatic hydrocarbon, or mineral oil.  Specified emulsifying agents are liquid polyglycol ethers of higher alcohols and of mercaptans and alkyl phenols.  The water emulsions should preferably contain 0.02 to 0.3 per cent of the dithiophosphoric acid ester.  Examples are given of pesticidal compositions comprising dithiophosphoric acid esters of the above formula wherein X is H, R3 is C2H5 and R1 and R2 are both methyl and both ethyl respectively; X is H, R3 is -CH2-CH = CH2 and R1 and R2 are both ethyl; R3 is C2H5, R1 and R2 are both ethyl, and X is CH3 and -CH2-O-C2H5 respectively; and in which R1 and R2 are both methyl, X is CH2OCH3 and R3 is C2H5 and -C(CH3)3 respectively.  Other dithiophosphates specified are those in which X is CH3, R3 is C2H5 and R1 and R2 are both methyl; X is CH2OCH3, R3 is C2H5 and R1 and R2 are both ethyl, and in which X is CH2OC2H5, R3 is C2H5 and R1 and R2 are both methyl. Specification 767,950 is referred to.