Patent GB-742796-A (GB)
Title: Organic derivatives of thiophosphoric acid
Inventor: LANE DAVID WILLIAM JOHN
IPC: C07F9/165
Filed: 1952-12-31
Abstract: The invention comprises new chemical compounds comprising sulphoxides of the general formula (RO)(R1O) P(O).S.C2H4.S(O)R11 wherein R, R1 and R11 are each an alkyl group containing not more than four carbon atoms and preferably not more than three carbon atoms. They may be prepared by oxidizing thioethers of the formula (RO)(R1O) P(O).S.C2H4.SR11 where R, R1 and R11 are as defined above with aqueous hydrogen peroxide under neutral conditions at not more than moderately elevated temperature to cause an oxygen atom to be added to a sulphur atom of the thioether.  The reaction may be carried out with or without a solvent.  In examples (1) a solution of (C2H5O)2 P(O)S.C2H4.S.C2H5 in water is mixed with 8 vol. hydrogen peroxide in water and maintained at 25.4 DEG  C. to yield O,O-diethyl-S-(ethylsulphinyl) - ethyl thiophosphate [(C2H5O)2 P(O).S.C2H4.S(O).C2H5]; (2) as in (1) except that 50 vol. hydrogen peroxide is used and the temperature is maintained at 70 DEG  C.; (3) as in (1) except that the starting material is stirred on a water bath at 70 DEG  C. and 50 vol. hydrogen peroxide added; (4) as in (1) except that the starting material is warmed to 60-70 DEG  C. with 100 vol. hydrogen peroxide; (5) 100 vol. hydrogen peroxide is added drop-wise to the compound (CH3O)2P(O).SC2H4SC2H5\t and the mixture maintained at 70-80 DEG  C. to yield the compound O,O - dimethyl - S - (ethylsulphinyl)-ethyl thiophosphate [(CH3O)2P(O).S.C2H4. S(O).C2H5]; (6) as in (5) except that the compound (CH3O)2P(O)SC2H4SCH3 is use as starting material the product being the compound O,O - dimethyl - S - (methylsulphinyl)-ethyl thiophosphate [(CH3O)2P(O).S.C2H4. S(O).CH3].  It is stated that each of the products of (1) to (4) can be reduced to the starting product by treating its solution in acetic acid with zinc dust for several hours.  The starting material in each example contains 32P the radioactive isotope of phosphorus. The compounds are stated to have systemic pesticidal properties (see Group VI).  Specification 691,374 is referred to.  According to the Provisional Specification the radicals R,R1 and R11 may be the same or different and each represents a methyl, ethyl, n-propyl or i-propyl group.ALSO:Pesticidal compositions comprise sulphoxides of the formula:-(RO)(R1O)P(O).S.C2H4.S(O).R11 where R, R1 and R11 are each an alkyl group containing not more than four carbon atoms, (see Group IV(b)) and if desired also a solid or liquid diluent or solvent.  The preferred diluent is water and it is desirable to add a wetting agent.  Suitable wetting agents are a product containing an alkylated phenol-ethylene oxide condensate, e.g. an iso-octylphenol-ethylene oxide condensate, and a product containing dioctyl sodium sulpho-succinate.  Liquid formulations may also be made with organic solvents such as acetone, benzene, chlorinated hydrocarbons, and alcohol, and may contain an emulsifier. Fumigants such as ethylene dibromide or 1, 2-dichloropropane may also be present.  Solid mixtures may be made by allowing the active ingredient to be adsorbed on inert finely divided material or cellulosic materials such as china clay, Fuller's earth, bentonite, talc powder and wood flour. Examples are given to compare the pesticidal action on aphids and red spiders of the compounds O, O-diethyl-S-(ethylsulphinyl)-ethyl thiophosphate (R, R1 and R11=ethyl); O, O-dimethyl-S-(methylsulphinyl)-ethyl thiophosphate (R, R1 and R11=methyl) and O, O-dimethyl - S - (ethylsulphinyl) - ethyl thiophosphate (R and R1 are methyl and R11 is ethyl) with the known compound diethyl S - b  - ethyl - mercapto - ethyl thiophosphate [(C2H5)2 O POS C2H4SC2H5].  Specification 691,374, [Group IV(b)], is referred to.