| 摘要 |
Process for the preparation of an ester useful as an intermediate in the manufacture of insecticidal pyrethroids having the general formula: <CHEM> wherein each of R<1> and R<2> independently represents an alkyl group of 1 to 4 carbon atoms or R<1> and R<2> together represent an alkylene group of up to 5 carbon atoms, each of X<1> and X<2> independently represents a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, a halogen atom, or X<1> and X<2> together represent an alkylene group of up to 5 carbon atoms, or X<1> represents a hydrogen atom and X<2> a 2-halovinyl group, a 2,2-dihalovinyl group or a 2 methyl-1-propenyl group and R represents a 2-methoxyethyl or a 2-ethoxyethyl group, characterized in that a substituted cyclopropanecarbonitrile having the general formula: <CHEM> wherein R<1>, R<2>, X<1> and X<2> have the same meaning as in formula I, is reacted with 2-methoxyethanol or 2-ethoxy-ethanol under substantially anhydrous conditions and in the presence of mineral acid acting as reaction catalyst and as scavenger for ammonia produced during the reaction. |
