| abstract |
New insecticides are of formula: <IMAGE> wherein R1 represents hydrogen or a methyl group; R2 represents hydrogen or a halogeno or lower alkyl group; R3 represents hydrogen or a halogen, lower alkyl (which is difference to R2 when R2 represents a lower alkyl group) or carboloweralkoxy group which contains at least 2 carbon atoms in the lower alkoxy residue when R2 represents methyl or R2 and R3 together with the carbon atom to which they are attached represent a cycloalkylene ring having at least one endocyclic carbon to carbon double bond; with the proviso that (a) R2 and R3 each represent hydrogen only when R1 represents methyl and (b) R3 contains at least 2 carbon atoms when R1 and R2 each represent hydrogen; and R represents a group which form insecticidal esters with chrysanthemic acid e.g. 5-benzyl-3-furylmethyl, 3-phenoxybenzyl, alpha -cyano-3-phenoxybenzyl. The esters are prepared by forming the ester linkage conventionally or by a Wittig reaction using a 3-formyl- or 3-acetyl-2,2-dimethyl cyclopropane carboxylic acid esterified with the desired residue or by an alkyl group which is subsequently converted to the desired residue. |