Use of a compound of formula (I) wherein R.sub.1 is selected from alkyl, aryl, alkoxy, aryloxy, 0thioalkyl, thioaryl, CN, halo, NR.sub.5R.sub.6, NR.sub.4COR.sub.5, NR.sub.4CONR.sub.5R.sub.6, NR.sub.4CO.sub.2R.sub.7 and NR.sub.4SO.sub.2R.sub.7; R.sub.2 is selected from N, O or S-containing heteroaryl groups, wherein the heteroaryl group is attached via an unsaturated carbon atom which is adjacent to one or two N, O or S-heteroatom(s), other than ortho, ortho-disubstituted heteroaryl groups; R.sub.3 is selected from H, alkyl, COR.sub.8, CONR.sub.9R.sub.10, CONR.sub.8NR.sub.9R.sub.10, CO.sub.2R.sub.11 and SO.sub.2R.sub.11; R.sub.4, R.sub.5 and R.sub.6 are independently selected from H, alkyl and aryl or where R.sub.5 and R.sub.6 are in an (NR.sub.5R.sub.6) group then R.sub.5 and R.sub.6 may be linked to form a heterocyclic ring; R.sub.7 is selected from alkyl and aryl; R.sub.8, R.sub.9 and R.sub.10 are independently selected from H, alkyl and aryl, or R.sub.9 and R.sub.10 may be linked to form a heterocyclic ring, or where R.sub.8, R.sub.9 and R.sub.10 are in a (CONR.sub.8NR.sub.9R.sub.10) group, R.sub.8 and R.sub.9 may be linked to form a heterocyclic group; and R.sub.1 is selected from alkyl and aryl, or a pharmaceutically acceptable salt thereof or prodrug thereof, in the treatment or prevention of a disorder in which the blocking of purine receptors, particularly adenosine receptors and more particularly A.sub.2A receptors, may be beneficial, particularly wherein said disorder is a movement disorder such as Parkinson's disease or said disorder is depression, cognitive or memory impairment, acute or chronic pain, ADHD or narcolepsy, or for neuroprotection in a subject; compounds of formula (I) for use in therapy; and novel compounds of formula (I) per se.