Patent ID: 7307175

Claim:
A process for the preparation of a compound of formula I wherein R is halogen, R 1 O, R 1 S(O) n or (R 1 ) 2 NC(X)O; R 1 is C 1 -C 8 alkyl, aryl-C 1 -C 8 alkyl, C 1 -C 8 haloalkyl or aryl; n is 0, 1, 2 or 3; X is O or S; and R 2 is hydrogen, C 1 -C 4 alkyl or C 1 -C 4 haloalkyl, in which process, in a solvent, (1) an aniline derivative of formula IV wherein R is as defined above, and R 3 is C 1 -C 5 alkyl or C 1 -C 5 haloalkyl, is diazotised in the presence of a mineral acid to form the corresponding diazonium salt of formula II wherein R and R 3 are as defined above, A m− is an anion, and m is 1 or 2, (2) the resulting diazonium salt of formula II is carbonylated in the presence of a catalyst, CO and optionally a buffer, to form a benzoic acid derivative of formula III wherein R and R 3 are as defined above, and (3) the benzoic acid derivative of formula III is then subjected to benzylic lactonisation in the ortho-position alkyl chain R 3 in the presence of a free-radical initiator and a halogenating agent.