Radiolabelled compound

1 . A process for producing a compound of formula (I)

which process comprises:

(i) treating an organoboron compound of formula (II) with 18 F − and a copper compound:

wherein

Z is a boronic ester group, a boronic acid group, a boronate group or a trifluoroborate group; and

R P is a protecting group of formula (III)

wherein

R 1 is C 1-6 alkyl;

R 2 is C 1-6 alkyl; and

R 3 is C 1-6 alkyl;

and

(ii) removing the protecting group R P to produce the compound of formula (I).

2 . The process according to claim 1 , wherein the copper compound is a copper salt.

3 . The process according to claim 1 , wherein the copper compound is [(impy) 4 Cu II (OTf) 2 ].

4 . The process according to claim 3 , wherein the [(impy) 4 Cu II (OTf) 2 ] is formed in situ from impy and a compound of formula [L n Cu(OTf) 2 ], wherein n is an integer from 0 to 4 and each L is a ligand other than impy.

5 . The process according to claim 1 , wherein Z is a group of formula (IV):

wherein:

each Q is the same or different and is a group selected from —OR E , —OH, and fluoride;

each R E is the same or different and is a group selected from substituted or unsubstituted C 1-10 alkyl, substituted or unsubstituted C 2-10 alkenyl, substituted or unsubstituted C 2-10 alkynyl, substituted or unsubstituted C 3-10 cycloalkyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, acyl, ester, amido, and haloalkyl, wherein two or more R E groups may be bonded together to form one or more rings; and

y is 2 or 3.

6 . The process according to claim 5 , wherein Z is a group selected from

7 . The process according to claim 1 , wherein the copper compound is [(impy) 4 Cu II (OTf) 2 ] and Z is

8 . The process according to claim 1 , wherein treating the organoboron compound of formula (II) with the 18 F − and the copper compound is carried out in the presence of a solvent.

9 . The process according to claim 8 wherein the solvent comprises 1,3-dimethyl-2-imidazolidinone (DMI), the copper compound is [(impy) 4 Cu II (OTf) 2 ], Z is a boronic ester group, and the ratio of the amount of the organoboron compound to the amount of the copper compound is from 3:5 to 3:4.

10 . The process according to claim 1 , wherein the organoboron compound, the copper compound and the 18 F − are heated at a temperature of from 80° C. to 150° C.

11 . The process according to claim 1 , wherein removing the protecting group R P comprises treatment with an acid, a source of boron trifluoride or a quaternary ammonium fluoride salt, optionally wherein removing the protecting group R P comprises treatment with an acid at a temperature of from 80° C. to 150° C.