Compounds of formula (I); wherein R.sub.1 is H or NHZ; R.sub.2 is optionally substituted aryl or heteroaryl attached via a carbon atom; R.sub.3 is H; optionally substituted C.sub.1-C.sub.6alkyl, C.sub.2-C.sub.6alkenyl, C.sub.2-C.sub.6alkynyl, or C.sub.3 C.sub.7 cycloalkyl, halogen; OH or OR, or R.sub.4 is H, optionally substituted C.sub.1-C.sub.6alkyl, C.sub.3 C.sub.6alkenyl, C.sub.3-C.sub.6alkynyl, C.sub.3-C.sub.7 cycloalkyl, aryl or heteroaryl, R.sub.5 is H or optionally substituted C.sub.1-C.sub.6alkyl, C.sub.3-C.sub.6alkenyl, C.sub.3-C.sub.6alkynyl, or C.sub.3-C.sub.7 cycloalkyl; or R.sub.4 and R.sub.5 together form a 5 or 6-membered heterocyclic ring; and R.sub.10 is optionally substituted C.sub.1-C.sub.6alkyl; are purine receptor, particularly adenosine receptor antagonists, useful for treatment of, inter alia, movement disorders such as Parkinsons disease.