Radiolabeled 1-aryl pyrazoles, the synthesis thereof and the use thereof as pest GABA receptor ligands

A radiolabeled compound of Formula I:

• or a salt thereof, where
• R1 represents R8, R8O, R8SO2, R8SO or R8S in which R8 is tritiated methyl, deuterated methyl, [13C]methyl or [14C]methyl;
• X is halo, cyano, C1-6 alkoxycarbonyl, C2-6 alkynyl, optionally substituted C6-14 aryl or an optionally substituted 5- to 7-membered heteroaromatic ring linked to thiazole via a carbon-carbon bond;
• R2 is hydrogen or amino;
• and
• R3-R7 each represent hydrogen, halogen, straight- or branched-chain C1-4 alkyl or C1-4 alkoxy, either of which is unsubstituted or substituted by one or more halogen atoms, straight- or branched-chain C1-4 alkylthio or C1-4 alkylsulphinyl, either of which is substituted by one or more halogen atoms, nitro, cyano, or straight- or branched-chain Ci1-4 alkylsulphonyl group which is unsubstituted or substituted by one or more halogen atoms.