Patent ID: 7642375

Claim:
A method for the preparation of a 11 C radiolabelled acid chloride compound of formula (I): R— 11 COCl (I) wherein R is C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 3 -C 10 cycloalkyl, C 3 -C 10 heterocyclyl, C 4 -C 10 aryl or C 4 -C 10 heteroaryl, any of which may optionally be substituted with NO 2 , —O(C 1 -C 6 alkyl), C 3 -C 10 cycloalkyl or C 4 -C 10 aryl; the method comprising reacting a 11 C radiolabelled carboxylic acid of formula (II): R— 11 COOH (II) wherein R is as defined for formula (I); with a solid-phase supported chlorinating agent in the presence of a base, wherein the solid-phase supported chlorinating agent is a solid-phase supported acyl chloride of formula III: [solid support]—linker—COCl (III) wherein the linker is a polyethylene glycol linker or comprises up to four groups selected from: C 4 -C 10 aryl or C 4 -C 10 heteroaryl groups; (CH 2 ) x groups where x is an integer from 1 to 20; (CH 2 ) y —O—(CH 2 ) 2 groups where y and z are integers from 1 to 20; or combinations thereof; wherein, in the linker groups, any CH 2 group may be replaced by —O—, —S—, —SO 2 — or —NH 2 — and the linker groups may be substituted with one or more substituents chosen from OH, halo, amino, nitro and C 1 -C 6 alkoxy.