Polyisonitriles and pesticidal compositions comprising them

The invention relates to poly isonitriles of the general formula C = N-A-N = C wherein A is an organic radical other than a hexamethylene radical which may contain 1-2 additional isonitrile groups. Preferably A represents an aliphatic, cycloaliphatic, aromatic araliphatic or heterocyclic bivalent radical, which may contain 1-2 additional isonitrile groups. These radicals may be substituted, in which case, they preferably contain one or more of the following groups: halogen, particularly chlorine; nitro, carboxy, carboxylic acid ester, carboxylic acid amide, nitrile groups, alkoxy, aryloxy, alkyl-mercapto, arylmercapto, alkyl-or aryl-sulphone, sulphonic acid, sulphonamide, acylamino, dialkylamino, alkyl-cycloalkyl, aralkyl or aryl radicals. In addition, A can represent two or more aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic radicals, these radicals being linked by bridges of the following types: -O-; -S-; -SO2-; -(CH2)1-10-; The compounds may be prepared by treating a formamide of the general formula OHC-NH-A-NH-CHO with a water eliminating agent, e.g. phosgene, in the presence of a tertiary base, e.g. a trialkylamine. Among many compounds claimed per se are di-(2-isocyano-2-methyl-1-propyl) carbonate, o ,o 1 - diisocyano - 2,3,5,6 - tetrachloro-p - xylene, 4,41 - diisocyano - 3,31 - diethoxydiphenyl 4,41 - diisocyano - 3,31 - dimethyl -5,51 - dichloro - diphenyl - methane, 4,41 -diisocyano-thiodiphenyl ether, 1,5-naphthylene diisocyanide, 2,7 - diisocyano - dibenzofuran, 1,4-diisocyanide, 4,41 - diisocyano - benzophenone, 3,31 - diisocyano - diphenylcarbonate, 1,4 -naphthylene diisocyanide, 1,5 - diisocyano -anthraquinone, tri - o,o,o - (p - isocyano-phenyl)-thiophosphate.ALSO:Pesticidal compositions comprises as active ingredient polyisonitriles of the general formula C = N - A - N = C wherein A is an organic radical other than a hexamethylene radical which may contain 1-2 additional isonitrile groups. Preferably A represents an aliphatic, cycloaliphatic, aromatic araliphatic or heterocyclic bivalent radical, which may contain 1-2 additional isonitrile groups. These radicals may be substituted. In that case, they preferably contain one or more of the following groups: halogen, particularly chlorine; nitro, carboxy, carboxylic acid ester, carboxylic acid amide, nitrile groups, alkoxy, aryloxy, alkyl-mercapto, arylmercapto, alkyl- or aryl-sulphone, sulphonic acid, sulphonamide, acylamino, dialkyla