GB949372A - Nitrile oxides - Google Patents

Abstract

The invention comprises compounds of the formula RX, where X represents a nitrile oxide group and R represents an aromatic nucleus having a halogen atom substituted in each position ortho to the nitrile oxide group. The compounds may be prepared by (1) reacting an aldoxime R.CH=NCH or a salt thereof with a hypochlorite, (2) reacting an aldoxime RCH=NOH with concentrated nitric acid at below 20 DEG C. and separating the nitrile oxide from the resulting mixture with a -nitro-aldoxime, e.g. by extracting the latter with aqueous ammonia or by selectively precipitating the former by adding water to an acetic acid solution of the mixture, (3) decomposing an g -nitro aldoxime RC(NO2)=NOH at below 50 DEG C. or (4) reacting with a base, e.g. an alkali-metal hydroxide or dicyanamide, ammonia or an organic base, a substituted aldoxime RC(Y)=NOZ, where Y is an anionic atom or group, e.g. a halogen atom or a cyano group, and Z is hydrogen or a cationic atom or group, e.g. an alkali-metal atom or an ammonium group. Examples describe the preparation of 2, 6-dichloro-, 2, 3, 6-trichloro- and 2-chloro-6-bromobenzo-nitrile oxide, and mention is made also of 2,6-dibromobenzonitrile oxide. Specification 949,371 is referred to. The Provisional Specification defines the products as being of the general formula R.C­N--> O, where R is (a) a group R1.O.CX3, R1.CO.-CX3 or R1.SO2.CX3, X being a halogen atom and R1 being a saturated or unsaturated, acyclic or cyclic, hydrocarbon group, or (b) a mono- or polycyclic hydrocarbon group in which the carbon atom in each position ortho to the nitrile oxide group either forms part of another carbocyclic ring or carries a halogen atom, an hydroxyl group, a carboxylic group, a sulphonyl group, a nitro group, a cyano group, a cyanate or isocyanate group, a perhalohydrocarbon group, a perhalohydrocarbyloxy group, e.g. -O-C(Halogen)3, a perhalohydrocarbylsulphonyl group, e.g. -SO2.C(Halogen)3, or a perhalohydrocarbylcarbonyl group, e.g. -CO.C(Halogen)3. The halogen may be present in a group containing fluorine, e.g. -CF3.-CF2Cl-CFCl2, -CFBr2 o -CF2Br. Pentachlorobenzonitrile oxide, 2,6-dichloro -4- nitrobenzonitrile oxide, 2,6-dichloro-3-hydroxygenzonitrile oxide, 2-chloro- (or 2-bromo) -1- naphthonitrile oxide and 9-anthronitrile oxide are among the compounds specifically mentioned.ALSO:Pesticidal and herbicidal compositions comprise compounds of the formula RX, where X represents a nitrile oxide group and R represents an aromatic nucleus having a halogen atom substituted in each position ortho to the nitrile oxide group (see Division C2). Examples describe the preparation of 2,6-dichloro-, 2,3,6-trichloro- and 2-chloro-6-bromobenzo-nitrile oxide, and mention is made also of 2,6-dibromobenzonitrile oxide. The nitrile oxides are particularly useful as pesticides, and for this purpose they may be mixed with surface-active agents, and (or) solid, including specified resinous or waxy carriers, liquid carriers, or gaseous carriers, and formulated as dusts, granules, pellets, wettable powders, liquid concentrates, solutions or emulsions of the oil in water or water in oil type. Many suitable carriers are specified, and the compositions may contain other ingredients also, e.g. sodium polyphosphates, cellulose ethers, sulphur, carbon, urea or hexamethylene tetramine and non-volatile oils. The nitrile oxides are useful also (a) for destroying the aquatic snails causing bilbarziasis, (b) as fungicides, (c) as bactericides, and (d) as herbicides, and brief particulars of their application to these purposes are given, 2,6-dichlorobenzonitrile oxide is useful also as a nematocide. Specification 949,371 is referred to. The Provisional Specification defines the products as being of the general formula R.C­N--->O, where R is (a) a group -R1.O.CX3, -R1.CO.CX3 or -R1.SO2.CX3, X being a halogen atom and R1 being a saturated or unsaturated, acyclic or cyclic, hydrocarbon group, or (b) a mono- or poly-cyclic hydrocarbon group in which the carbon atom in each position ortho to the nitrile oxide group either forms part of another carbocyclic ring or carries a halogen atom; an hydroxyl group, a carboxylic group, a sulphonyl group, a nitro group, a cyano group, a cyanate or isocyanate group, a perhalohydrocarbon group, a perhalohydrocarbyloxy group, e.g. -O-C(Halogen)3, a perhalohydrocarbylsulphonyl group, e.g. -SO2.C(Halogen)3, or a perhalohydrocarbyl-carbonyl group, e.g. -CO.C(Halogen)3. The halogen may be present in a group containing fluorine, e.g. -CF3-CF2CR, -CFCl2, -CFBr2 or -CF2Br. Pentachloro-benzonitrile oxide, 2 6 - dichloro - 4 p - nitrobenzonitrile oxide, 2,6-dichloro - 3 - hydroxybenzonitrile oxide, 2-chloro- (or 2-bromo)-1-naphtho-nitrile oxide and 9-anthronitrile oxide are among the compounds specifically mentioned. Specification 949,371 is referred to.