Patent GB-713278-A (GB)
Title: Process for the production of phosphoric acid esters and their use in the control of pests
IPC: C07F9/6558
Filed: 1952-04-21
Abstract: 713,278. Organic phosphates. GEIGY AKT.-GES., J. R. April 21, 1952 [April 20, 1951], No. 9903/52. Class 2 (3). [Also in Group VI] The invention comprises esters of the formula wherein R-X- represents the radical of the enol form R-X-H of a non-condensed heterocyclic compound having an endocyclic enolizable keto or thioketo group, which may be substitued, R 1  and R 2  represent alkyl radicals and X, X 1  and X 2  represent oxygen or sulphur. Such esters are obtained by reacting a compound of the formula where Hal represents chlorine or bromine with the appropriate non-condensed heterocyclic compound having an endocyclic enolizable keto or thioketo group or with a salt of the enol form of such a compound. Esters of the first formula where X, X 1  and X 2  represent oxygen and X 3  represents sulphur may also be obtained by reacting a heterocyclic sulphonyl halide of the general formula R-S-Hal, wherein Hal represents chlorine or bromine with a phosphorus and diester of the formula HOP(OR 1 )OR 2  or HPO(OR 1 )OR 2 . Reaction in a solvent in the presence of an acid-binding agent is preferred. Specified as heterocyclic compounds are: dioxotetrahydrofurane derivatives, e.g. 3-methyl-, 3-ethyl-, 3-isopropyl- and 3 - isoamyl - 2 : 4 - dioxotetrahydrofurane; 3- and 5-pyrazolones containing one or more methyl, ethyl, isopropyl, isoamyl, cyclohexyl, phenyl, m-chlorophenyl, p-nitrophenyl, p-methoxy-phenyl, benzyl, 2-pyridyl, chlorine, nitro, or carbethoxy groups; 3 : 5- diketo-pyrazolidines, e.g. 1-methyl-, 1-phenyl-, 1 : 2-diphenyl-, and 1 : 2-diphenyl-4-butyl-3 :5- diketo-pyrazolidine; 3-methyl- and 3-phenyl isoxazolone-(5); imidiazolone-(2); 1-phenylimidazolone-(2); 2-methyl-imidazolone-(4); 4- methyl- or phenyl-2-hydroxy-thiazole; triazolones, e.g. 1-phenyl-5-hydroxy-1 : 2 : 3-triazole and 1 : 2 : 4-triazolones containing one or more phenyl, propyl, methyl, or isobutyl radicals; 3-phenyl-1 : 2 : 4-oxodiazolone; 3- methyl - pyrone - (2) - one - (4), 2 - methyl - 3- hydroxy - γ - pyrone; 5 : 6 - diphenyl - 3- hydroxy - 1 : 2 : 4 - triazine; 2 - methyl - 5- hydroxy - 1 : 3 : 4 - oxdiazine; 4 - methyl - 2- mercaptothiazole; 1 - methyl - 2 - mercaptotriazole - (1 : 3 : 4); 1 - phenyl - 3 - methylpyrazole - thione - (5); imidazole - thione- (2); 1 - phenyl - imidazole - thione - (2); 4 : 6- dimethyl - pyridone - (2); 2 : 6 dimethyl - 4- hydroxy-, 2- and 4-mercapto-, and 4-mercapto- 2 : 6 - dimethyl - pyridines; 2 : 4 - dimethyl- 6 - hydroxy - 2 - propyl - 4 - methyl - 6 - hydroxy-, 6-mercapto-2- or 4-methyl-, 6-mercapto- 2 : 4 - dimethyl -, and 6 - mercapto - 2- methylmercapto - pyrimidines. Compounds which in the alkyl, aralkyl and aryl radicals substituted in the heterocyclic ring contain halogen, nitro, alkoxy, alkylmercapto, halogenated methyl, e.g. trifluoromethyl, aryloxy, arylmercapto, substituted and acylated amino, alkyl and aryl sulphoxide and sulphone, halogenated alkyl sulphone, carbalkoxy, carbamino, cyano, rhodane or sulphonamide groups. The phosphoric acid diester halides may be derived from methanol, ethanol, n-propanol, isopropanol, allyl alcohol, butyl and amyl alcohols, n-hexanol, methoxyethanol, ethoxyethanol, methylmercapto - ethanol, butoxy - ethanol, 2-chlorethanol, 2-fluorethanol, 2 : 3-dichloropropanol, methyl-, ethyl-, n-propyl-, isopropyl butyl and amyl mercaptans, methoxyethyl-mercaptan, methyl-mercapto-ethyl-mercaptan and 2-chlorethyl-mercaptan, by reaction with phosphorus oxyhalides or thiohalides. In examples there are prepared (1) 2 : 4-dimethylpyrimidyl-(6)]-diethyl-thiophosphoric acid ester from 2 : 4-dimethyl-6-hydroxypyrimidine and diethyl-thiophosphoric acid chloride; (2) 3- methyl - pyrazolyl - (5) - diethyl thiophosphoric acid ester by reacting the sodium salt of 3- methyl-pyrazolone-(5) with diethyl thiophosphoric acid chloride; (3) 2: 6-dimethyl-pyridyl- (4)-di-isopropyl phosphoric acid ester by reacting the sodium salt of γ-lutidone with di-isopropyl phosphoric acid chloride ; (4) S-[4- methyl - thiazolyl - (2)] - diethyl thiophosphoric acid ester from 4-methyl-thiazole-2-sulphonyl chloride and triethyl phosphite. In a table there are listed further compounds of the first formula, the group R-X- being selected from the tetrahydrofurane, pyrazolone and pyrimidine derivatives mentioned above (allyl and cyclohexyloxyethyl being additional substituents in the heterocyclic nucleus), and the groups R 1  and R 2  being methyl, ethyl, isopropyl, butyl, 2-ethyl-hexyl radicals. The products are useful as pesticides (see Group VI).