Patent GB-968775-A (GB)
Title: New heterocyclic dithiophosphoric acid esters
IPC: A01N57/16
Filed: 1962-11-01
Abstract: The invention comprises a phosphorus-containing tetrahydrothiophene derivative of the formula: <FORM:0968775/C1/1> wherein Z is hydrogen or (RO)2P(S)S- and R is an alkyl radical preferably having 1 to 5 carbon atoms.  The derivatives in which Z is hydrogen may be obtained by condensing a dialkyl phosphorodithioate (RO)2P(S)SH with 2,5-dihydrothiophene and the derivatives in which Z is (RO)2P(S)S may be obtained by reacting 2,5-dihydrothiophene with a dialkyl phosphorodithioate disulphide of the formula(RO)2P(S)S2 Alternatively, the derivatives of each type may be obtained by reacting a dialkyl phosphorodithioate or its disulphide as defined above with 1,4-dichloro-2-butene and contacting the resultant 2- or 2,3-bis-(dialkylphosphorodithioate)-1,4-dichlorobutane with at least one molar equivalent of a metal sulphide, preferably an alkali metal sulphide such as sodium sulphide, the reaction being preferably carried out in a solvent e.g. one of those specified below. The reaction in the first type of process may be carried out by adding either reactant to the other reactant dissolved in an inert solvent e.g. an alkane, aliphatic alcohol, ketone, ester, aromatic hydrocarbon or chlorinated aromatic hydrocarbon. The reaction may suitably be effected at near the reflux temperature of the solvent and at atmospheric or sub-atmospheric pressure or the reaction may be carried out in a closed system. When the disulphide is used as reactant a small amount of iodine is preferably used as catalyst. Examples are given and the products have insecticidal properties (see Division A5).ALSO:An insecticidal composition comprises a carrier in association with a phosphorus-containing tetrahydrothiophene derivative of the formula <FORM:0968775/A5-A6/1> wherein Z is hydrogen or (RO)2P(S).S- and R is an alky' (preferably C1-C5 alkyl) radical (see Division C2). The active ingredient may be used in combination with other insecticides such as D.D.T., methoxychlor, lindane, aldrin, endrin, DDD, BHC, parathion, "Malathion" (Trade Mark), methyl parathion, lead arsenate, calcium asrenate, rotenone, allethrin, pyrethrum, nicotine, summer oils, dormant oils, dinitroalkylphenols, dinitrocresols, chlordane, heptachlor, chlorinated terpenes, demeton, and organophosphates, thiophosphates, dithiophosphates such as Guthion, Diazinon and Dibrom and the compound dodecachloro-octahydro-1,3,4 - methens - 2H - cyclobuta - (cd)pentalene (C10Cl12).  A fungicide such as 5-amino or 5-nitro - 2,3,6 - trihalophenylacetic acid may also be present.  The composition may be in the form of a solid, e.g. dust, wettable powder, pellets, or granules, or may be a liquid composition in which the insecticide is in dissolved, dispersed or emulsified form. Suitable solid carriers include talc, clays, flours, silica, alkaline earth metal carbonates, oxides and phosphates, and sulphur.  Examples of suitable compositions are given and an additional example is included in which O,O-diethyl S-(1,4 - dichloro - 2 - butyl) phosphorothiolothionate is mixed with activated carbon in the ratio of 10 to 90 parts by weight to form a powder suitable for use as a seed dressing.