Patent ID: 7321043

Claim:
A process for the preparation of a compound of the formula (II): or a salt thereof, wherein X is halogen; each Y, which may be the same or different, is halogen, haloalkyl, alkoxycarbonyl or alkylsulphonyl, and n is 0 to 3; which process comprises treating a compound of the formula (III): with a cyanide source and a catalyst selected from the group consisting of a tetraalkyl ammonium salt and a tetraalkyl phosphonium salt in an aqueous solvent or without solvent, wherein: X is halogen; each Y, which may be the same or different, is halogen, haloalkyl, alkoxycarbonyl or alkylsulphonyl: and n is 0 to 3; and wherein the cyanide source is hydrogen cyanide, an alkali metal cyanide, an alkaline earth metal cyanide or an optionally substituted ammonium cyanide.