Patent GB-681376-A (GB)
Title: Manufacture of heterocyclic carbamic acid derivatives and their use as agents for combating pests
IPC: C07D277/68
Filed: 1949-11-23
Abstract: The invention comprises esters of dialkyl carbamic acids (alkyl of 1-4 carbon atoms) with enols of heterocyclic oxo compounds in which the oxo group is part of the heterocyclic ring.  Preferably the enols are of 5- and 6-membered heterocyclic compounds with alkyl or aryl substituents.  The esters are prepared by reacting the enol or a metal salt thereof with a reactive derivative of the carbamic acid, e.g. the halide or phenyl ester.  The reaction may take place in the presence or absence of solvents and acid-binding agents.  Examples show the production of dimethyl, diethyl and dibutyl carbamates of the following: a -ethyl, a -n- and isopropyl and a -n-butyl-tetronic acids, 1-methylindazol - 3 - one, 6 - methyl - pyronone, 1-phenyl-3-methyl-5-pyrazolone and the following substituted phenyl compounds: 41-methyl, 31-chloro, 21 : 51- and 31 : 41-dichloro, 41-methoxy, 41-ethoxy, 41-amino, 41-cyano and 21-methyl-51-methylsulphonyl; 1-phenyl, 1 : 2-diphenyl and 1 : 2-diphenyl-4-n-butyl-3 : 5-pyrazolidiones, 2 : 6-lutidone (4), 2-ethyl-4-methyl-, 2-propyl-4-methyl- and 2 : 4-dimethyl-6-hydroxypyrimidines, 1-phenyl-1 : 2 : 4-triazol-5-one and the following substitution products: 3-methyl, 3-ethyl and 3-propyl; 1 - phenyl - 1 : 2 : 4 - triazol - 3 - one and substituted products: 4-methyl, 5-ethyl and 5-propyl; 5-pyrazolones: 3-methyl, 1-ethyl-3-methyl, 1-benzyl-3-methyl, 1-phenyl-3-benzyl, 1 : 3-diphenyl, 1-phenyl, 3-phenyl, 1-phenyl-3-ethyl and 1-cyclohexyl-3-methyl; 1-phenyl-5-methyl-3 - pyrazolone, 1 - phenyl - 4 - pyrazolone, 4-methyl - 2 - thiazolone, benz - 2 - thiazolone, 2 - methyl - 1 : 3 : 4 - oxadiazol - 5 - one, benzotetronic acid, 2- and 4-pyridones, 4 : 6-dimethy-2-pyridone and 5 : 6-diphenyl-1 : 2 : 4-triazin-3-one. Other compounds are listed, containing the following additional ring-systems: imidazole, isoxazole, pyridazine, indole, thionaphthene, benzisothiazole, benzoxazole, quinoline, benzoparathiazine, quinazoline and quinoxaline.  There are also specified the following carbamic acids: di-n-and isopropyl, methylethyl, methylisopropyl and methyl-n-butyl.  Substituents that may be present in aromatic rings are: chlorine, bromine, fluorine, nitro, alkyl, alkoxy, alkylthio, trifluoromethyl, aryloxy, arylthio, acylamino, alkyl and aryl sulphoxide and sulphone, chloromethylsulphone, trifluoromethylsulphone, carboxylic ester or amide, cyano, thiocyano or sulphonamide.  A further example is given in the Provisional Specification of the reaction between 1-phenyl-5-pyrazolone-3-carboxylic ethyl ester and dimethylcarbamic chloride.  Carbamyl halides used as starting materials are obtained from the secondary amines and carbonic dihalides, e.g. phosgene. Dialkylcarbamic phenyl esters are produced from the secondary amines and phenyl chloroformate.ALSO:Compositions for combating pests comprise a dialkylcarbamic ester (Alkyl containing 1-4 carbon atoms) of an enol of a heterocyclic oxo compound with a carrier or distributing agent, with or without other substances with bactericidal, fungicidal or insecticidal properties.  Preferred esters are those of enols of 5- and 6-membered heterocyclic compounds with alkyl or aryl substituents.  The compositions may be in the form of powders, suspensions, solutions, aerosols, emulsions or ointments. Solid carriers may be calcium carbonate, kaolin, bole, bentonite, talcum, magnesia, boric acid, kieselguhr, tricalcium phosphate, powdered wood, cork or other vegetable matter.  Suspensions in water are made from such mixtures with a wetting agent and protective colloid.  Solutions of the esters in kerosene, methylnaphthalene, xylene and other high-boiling solvents are used for spraying.  For mists and aerosols there are used low-boiling solvents such as trichlorethylene, tetrachlorethane, ethylene chloride, fluorotrichloromethane and difluorodichloromethane. For impregnation of textiles these low-boiling solvents are applicable, also benzene, xylene, chlorobenzene, alcohol and acetone.  Constituents of emulsions are wetting agents of the cation-active, anion-active and non-ionic types, acetone, p  alcohols, cyclohexanone, benzene, toluene, xylene, tetrahydronaphthalene, alkylnaphthalenes, phthalic esters, mineral and vegetable oils and resins.  The active ingredients may be mixed with a lure (e.g. sugar) to form a bait in the form of a dust, spray or flypaper.  Adhesives and water-repellents may be added, e.g. fatty acids, resins, glue, casein or alginates.  Other substances with bactericidal, fungicidal or insecticidal activity may be present, e.g. chlorinated phenols, quaternary ammonium compounds, sulphur, copper compounds, fluorides, DDT, benzene hexachloride, p-nitrophenyldiethyl-thiophosphate, tetraethyl pyrophosphate, chlorinated camphene, chlordane, the dimethylcarbamate of 5:5-dimethyldihydroresorcinol, pyrethrin and rotenone.  In the examples, the dimethylcarbamates of the following heterocyclic compounds are combined with the stated ingredients:-(1) 3-methyl-5-pyrazolone with talc, fatty acid and quenched lime, (2) 1-phenyl-3-methyl-1:2:4-triazol-5-one with kaolin, colloidal silicic acid and sulphite waste liquor emulsified in water, (3) 1-phenyl-3-methyl-5-pyrazolone with limestone, (4) 6-methylpyronone with xylene and kerosene, (5) 1-phenyl-3-methyl-5-pyrazolone with DDT, xylene and kerosene, (6) 1-phenyl-3-methyl-5-pyrazolone with water, solubilised by ethanol or isopropanol, with or without wetting agents or adhesives, (7) 1-ethyl-3-methyl-5-pyrazolone with water, polyglycol ethers and isopropanol, (8) 1-phenyl-5-pyrazolone with sawdust and potassium nitrate burnt for smoke, (9) 2:4-dimethyl-6-pyridone with sugar, potassium chlorate, potassium nitrate and sawdust burnt for smoke, (10) 1-phenyl-5-pyrazolone with acetone, xylene and polyglycol ethers emulsified in water, (11) 1-phenyl-3-methyl-5-pyrazolone with diacetone alcohol and polyglycol ethers emulsified in water; there may be added to the above emulsions natural and artificial resins, dextrine, starch, waterglass and adhesives for resistance to rain when sprayed on plants; (12) 1-phenyl-3-methyl-1:2: 4-triazol-5-one with acetone, carbon tetrachloride or trichlorethylene as spray, (13) 3-methyl-5-pyrazolone above or with additives which help vaporisation heated to produce an insecticidal gas.  Many other suitable carbamates are listed containing the following ring-systems in addition to the above:-furan, coumarone, indole, quinoline, imidazole, pyridazine, pyrimidine, indazole, quinazoline, quinoxaline, 1:2:4-triazine, thiazole, oxadiazole, isoxazole, benzthiazole, benzoxazole, benzisothiazole, thionaphthene and benzoparathiazine.