Patent GB-920420-A (GB)
Title: Improvements in or relating to thiophosphoric esters, their preparation and their uses
IPC: C07F9/6533
Filed: 1959-06-30
Abstract: The invention comprises thiophosphoric ester compounds of the general formula:-(RO)2P(X1).X2.A.Y.B.CON(R1) (R2) in which X1 and X2 are the same or different and represent oxygen or sulphur atoms, at least one of them being a sulphur atom, A is an ethylene or isopropylene group, B is a methylene or ethylidene group, Y is the group SO or SO2, R is a C1-C4 alkyl group and R1 and R2 are the same or different and each represents a hydrogen atom, a C1-C4 alkyl group, a phenyl group or a cyclohexyl group, or R1 and R2 together with the N atom attached thereto represent a saturated heterocyclic radical such as piperidino, pyrrolidino, or morpholino.  The compounds in which both X1 and X2 are sulphur atoms and A is an ethylene group may be obtained by reacting a dithiophosphoric acid of the formula: (RO)2P(S)SH with a compound of the formula: CH2=CH-Y-B-CON(R1)(R2). The reaction is preferably carried out in an organic solvent medium at below 150 DEG C., the solvent being suitably an aliphatic alcohol or ketone or an aromatic hydrocarbon.  The compounds of the given general formula may also be obtained by oxidising a compound of the general formula (RO)2P(X1)X2ASBCON(R1) (R2) by treatment with hydrogen peroxide at below 50 DEG C. to convert the sulphur atom to SO or by treatment with a stronger oxidising agent, e.g. potassium permanganate or potassium dichromate, at below 50 DEG C. to convert the sulphur atom to SO2.  This reaction may be carried out with or without a solvent, e.g. water.  Examples are given for the production of N-methyl-5-(O,O-diethyldithiophosphoryl)-3-thia-3-dioxo-valeramide; N-methyl-5-(O,O-diethyldithiophosphoryl) -3-thia-3-oxo-2-methyl-valeramide; 5-(O,O-diethyldithiophosphoryl)-3-thia-3-oxo-valeramide and the corresponding 3-dioxo compound.  The products have pesticidal properties (see Group VI).  The starting materials of the formula CH2=CH.Y.B.CON(R1)(R2) may be obtained by dehydrohalogenation by means of triethylamine of the corresponding 5-halogenovaleramide.  N- methyl-5-chloro-3-thia-3-dioxovaleramide is obtained by oxidation of N-methyl-5-chloro-3-thia-valeramide with excess hydrogen peroxide in acetic acid. N-methyl-5-chloro-3-thia-3-oxo-2-methylvaleramide and 5-chloro-3-thia-3-oxo-valeramide respectively are obtained by oxidation of the corresponding -3-thiacompounds with hydrogen peroxide, also 5-chloro-3-thia-3-dioxo-valeramide is obtained by oxidation of 5-chloro-3-thia-valeramide with excess hydrogen peroxide in acetic acid.  Specification 872,823 is referred to.ALSO:A pesticidal composition comprises, in association with a solid or liquid diluent, a thiophosphoric ester of the formula (RO)2P.(X1)X2.A.Y.B.CON(R1)(R2) in which X1 and X2 which are the same or different are oxygen or sulphur atoms, at least one of them being a sulphur atom, A is an ethylene or isopropylene group, B a methylene or ethylidene group, Y is SO or SO2, R is a C1-C4 alkyl group and R1 and R2 are the same or different and are hydrogen atoms, C1-C4 alkyl groups, phenyl or cyclohexyl groups, or R1 and R2 represent with the N-atom attached thereto a saturated heterocyclic radical, e.g. piperidino, pyrrolidino or morpholino (see Group IV (b)). Specified diluents for solid compositions are talc, calcined magnesia, kiselguhr, tricalcium phosphate, powdered cork, absorbent charcoal, a clay, e.g. kaolin or bentonite.  The composition may also be in the form of an aerosol, a suspension, an emulsion or a solution in an organic or aqueous organic medium, e.g. toluene, xylene, a mineral, animal, or vegetable oil, or a mixture thereof.  Wetting, emulsifying or dispersing agents may be present.  A list of such surface active agents is provided. Other pesticides may also be present. Specification 872,823 is referred to.