Patent GB-812530-A (GB)
Title: Phosphonic and thiophosphonic acid derivatives
IPC: A01N57/22
Filed: 1957-08-22
Abstract: The invention comprises phosphonic acid esters of the general formula: <FORM:0812530/IV (b)/1> wherein R and R1 represent alkyl (preferably C1-4) or aryl (preferably phenyl) radicals, Ar represents an aryl (preferably phenyl) radical, R2 represents a C1-4 alkyl radical, X represents oxygen or sulphur, and n is 0, 1 or 2. They are prepared by reacting phosphonic- or thionophosphonic acid halides, especially chlorides, with suitable substituted phenols.  Suitable phosphonic acid halides include methyl, ethyl and propyl phosphonic acid ethyl ester chlorides; phenyl, p-chlorophenyl and 3,4-dichlorophenyl phosphonic acid ethyl esters chlorides; also the corresponding thionophosphonic acid derivatives and other alkyl esters such as the methyl, propyl and butyl esters.  Suitable phenols include alkylmercaptophenols, phenylmercaptophenols, alkylmercaptocresols, 2-ethylmercapto - p - chlorophenol, 2 - methyl - mercapto - p - chlorophenol, 2 - phenylmercapto - p-chlorophenol; also the corresponding sulphoxides and sulphones.  In the case of preparing the sulphoxides or sulphones, the mercaptophenyl phosphonic acid products may be oxidized thereto.  The phosphonic ester halides are generally reacted with salts of the phenols, especially alkali metal salts such as the sodium or potassium salt or with the phenols in the presence of acid binding agents especially alkali metal alcoholates, hydroxides or carbonates.  The reaction temperature is generally 0-100 DEG C. although higher or lower temperatures may be used.  Generally, the reaction is started at a relatively low temperature or at room temperature and completed on the steam bath. The presence of inert solvents is desirable, e.g. acetone, lower alcohols such as methanol or ethanol, benzene or toluene.  The compounds are insecticides and plant-protecting agents.  Examples describe the preparation from the appropriate phenol or a salt thereof and phosphonic ester chloride of: (1) ethyl p-methylmercaptophenyl methylphosphonate; (2) ethyl p-methyl-sulphinylphenyl methylphosphonate; (3) ethyl p-methylsulphonylphenyl methylphosphonate; (4) ethyl o-methylmercaptophenyl methylphosphonate; (5) o-ethylmercaptophenyl iso-propyl methylphosphonate; (6) ethyl p-methylmercaptophenyl methylthionophosphonate; (7) methyl p-methylmercaptophenyl methylthionophosphonate; (8) methyl p-methylsulphinylphenyl methylthionophosphonate; (9) methyl p-methylsulphonylphenyl methylthionophosphonate; (10) p-ethylmercaptophenyl methyl methylthionophosphonate; (11) ethyl p-ethylmercaptophenyl methylthionophosphonate; (12) methyl o-methylmercaptophenyl methylthionophosphonate; (13) ethyl o - methylmercaptophenyl methylthionophosphonate; (14) methyl 4-methyl-2-methylmercaptophenyl methylthionophosphonate; (15) 4 - chloro - 2 - methylmercaptophenyl methyl methylthionophosphonate; (16) ethyl 2-methylmercapto - 4,6 - di - isopropyl methylthionophosphonate; salts of some of the phenols are prepared by the action of sodium methylate on the phenol; solvents used are acetone, methyl ethyl ketone or benzene; potassium carbonate is used as acid binding agent where the free phenol is used.ALSO:Insecticidal and plant protecting compositions comprise phosphonic acid esters of the general formula <FORM:0812530/VI/1> wherein R and R1 represent alkyl (preferably C1-4) or aryl (preferably phenyl) radicals, Ar represents an aryl (preferably phenyl) radical, R2 represents a C1-4 alkyl radical, X represents oxygen or sulphur, and n is 0, 1 or 2. Other substances which may be present include solid or liquid carriers, e.g. chalk, talc, bentonite, water, alcohols, liquid hydrocarbons, and other active agents, e.g. known insecticides or pesticides.  Generally 0.001-1 per cent of active compound is present.  The compositions may be applied in any manner e.g. as dusts, sprays or aerosols.  A composition containing ethyl p-methylmercaptophenyl methylthionophosphonate, together with dimethyl formamide, a benzyl hydroxy diphenyl polyglycol ether and water is described.