Patent ID: 7094906

Claim:
A process for the preparation of a compound of formula (X) or (XI): wherein R 1 represents halogen, haloalkyl, haloalkoxy, —SF 5 , or R 4 S(O) n —, wherein R 4 represents alkyl or haloalkyl, and n represents 0, 1 or 2; R 2 represents hydrogen or halogen; and W represents CR 3 , wherein R 3 represents halogen; which process comprises reacting a compound of formula (I): wherein R 1 , R 2 and W are as defined above, with a source of hydrogen cyanide, to produce the corresponding compound of formula (VI): wherein R 1 , R 2 and W are as defined above; followed by oxidizing the compound of formula (VI) thus obtained and optionally reacting it with a base.