Patent GB-901551-A (GB)
Title: Thiophosphinic acid derivatives
IPC: C07F9/6521
Filed: 1959-03-18
Abstract: The invention comprises thiophosphinic acid derivatives of the general formula:-  <FORM:0901551/IV (b)/1> wherein X and Y are oxygen or sulphur, at least one of them being sulphur, R1 and R2 are C1-C4 alkyl radicals, cycloalkyl radicals or unsubstituted or substituted aryl radicals, at least one of them being an alkyl radical containing 1 to 4 carbon atoms, and R3 is a substituted alkyl or substituted alkenyl radical or an unsubstituted or substituted aryl radical or a cycloalkyl or heterocyclic radical.  They may be obtained by (a) reacting salts of the formula (R1)(R2)P(X)YMe with a compound of the formula Hal.R3, Me being an alkali metal or ammonium and Hal being a halogen atom, or (b) by reacting a compound of the formula (R1)(R2)P(X)Cl with either a compound R3.YH in the presence of an acid binding agent or with a compound R3YMe in which Me is an alkali metal in which case no acid-binding agent is required.  Compounds in which X is oxygen and Y is sulphur may also be obtained by reacting a thiophosphinic acid in an alkaline medium whereby it reacts in the tautomeric form (R1)(R2)P(O)SH with a compound R3Hal in which Hal is a halogen atom or by reacting a salt of the tautomeric form of the thionophosphinic acid with the compound R3Hal.  Also, products in which R3 in the general formula is -C2H4-X1R may be obtained by reacting a compound (R1)(R2)P(X).SH with a vinyl ether or thioether of the formula CH2=CH.X1R wherein X1 is oxygen or sulphur and R is an alkyl or aryl radical. Some of the products may also be prepared by a stepwise process in which chlorobromomethane is reacted with a dithiophosphinic acid to yield the chloromethyl ester of the latter and said ester is then reacted with a mercaptan or with a second molecule of a thio- or dithiophosphinic acid.  When R2 is aryl it may be substituted e.g. by chlorine, bromine, nitro groups, C1-C4 alkoxy groups, or C1-C4 alkylmercapto groups.  Suitable substituents when R3 is substituted alkyl are alkoxy, alkylmercapto, primary or secondary amino, carbalkoxy, or aryl groups which latter may be substituted by halogen atoms or any of the aryl substituents mentioned above; amido groups, alkylamino-carbonyl groups, or cyano groups.  The radical R3 when aryl may be substituted e.g. by C1-C4 alkyl groups, halogen atoms e.g. Cl or Br, nitro groups, alkoxy, alkylmercapto, or carbalkoxy groups or an acetyl group.  When R3 is heterocyclic it may be the radical derived from e.g. 1,4-dioxane, g -pyrone or benzazimide but several other heterocyclic radicals are specified.  A special class of products of the first given general formula is obtained by reaction (b) above using as the hydroxy or thiol compound the enol forms of keto or thioketo compounds, e.g. acetoacetic acid esters, malonic esters, malonic ester amides, dihydroresorcinols, diketotetrahydrofuranes, pyrazolones, 3,5-diketopyrazolidines and the enolic forms of other analogous heterocyclic compounds several of which are specified.  Several examples are given, the products including the compounds:  (CH3)2P(S)SCH2O(or S)CH2S(S)P(CH3)2.  The products have insecticidal properties (see Group VI).  Salts of dithiophosphinic acids (R1R2PS.S.Me wherein Me is an alkali metal) may be obtained by reacting the corresponding thiophosphinic acid chloride with an alkali metal hydrogen sulphide.  Thiophosphinic acid chlorides (R1)(R2)P(S)Cl may be obtained by reacting a bis-thionophosphine of the formula (R1)(R2)P(S).P(S)R1R2 with chlorine or sulphuryl chloride or by reacting a thiolphosphonite (R1)(R2)P(S)H with carbon tetrachloride.  Phosphinic acid chlorides may be obtained by reacting the corresponding phosphinic acid alkyl ester in which the alkyl group is C1-C4 with thionyl chloride and the preparation of methyl-phenyl-phosphinic acid chloride, ethyl p-chlorophenyl phosphinic acid chloride, methyl - 4 - methyl-2-chlorophenyl-phosphinic acid chloride and methyl p-methylmercaptophenyl phosphinic acid chloride is described. Dimethylthionophosphinic acid may be obtained by reacting (CH3)2P(S)Cl with an aqueous solution of sodium hydroxide. Di-n-propyl thiophosphinic acid may be obtained by a similar process. Specification 784,612 is referred to.ALSO:An insecticidal composition contains as active ingredient a thiophosphinic acid derivative of the formula <FORM:0901551/VI/1> wherein X and Y are oxygen or sulphur, at least one of them being sulphur, R1 and R2 are C1 C4 alkyl radicals, cycloalkyl radicals or unsubstituted or substituted aryl radicals, at least one of them being an alkyl radical containing 1 to 4 carbon atoms, and R3 is a substituted alkyl or substituted alkenyl radical or an unsubstituted or substituted aryl radical or a cycloalkyl or heterocyclic radical (see Group IV (b)) and an inert solid or liquid carrier or diluent.  Specified diluents are talc, chalk, bentonite, clay, water (if necessary with an emulsifier), alcohols, ketones and liquid hydrocarbons. The active ingredient may be used in combination with known insecticides and/or fertilizers.  When R2 is aryl it may be substituted, e.g. by Cl, Br, NO2, or C1-C4 alkoxy or C1-C4 alkylmercapto groups.  Suitable substituents when R3 is substituted alkyl are alkoxy, alkylmercapto, primary or secondary amino, carbalkoxy or aryl groups which latter may be substituted, e.g. by C1-C4 alkyl groups, halogen atoms, or any of the aryl substituents mentioned above; amido groups, alkylaminocarbonyl groups or cyano groups.  When R3 is aryl it may be substituted, e.g. by C1-C4 alkyl groups, halogen atoms, e.g. Cl or Br, nitro groups, alkoxy, alkylmercapto or carbalkoxy groups or an acetyl group.  When R3 is heterocyclic it may be the radical corresponding to 1,4-dioxane, g -pyrone or benzazimide but several other heterocyclic radicals are mentioned.  A large number of active ingredients of the above formula are specified including the compounds: (CH3)2P(S)S.CH2.O (or S) CH2.S(S)P(CH3)2.  Specification 784,612 is referred to.