There are described Compounds of formula (I) in which R3 to R8 are independently selected from hydrogen, halogen, trihaloalkyl, alkyl having 1, 2, 3, 4 or 5 carbon atoms, electron donor groups selected from alkoxy having 1, 2, 3, 4 or 5 carbon atoms, trihaloalkoxy, hydroxy or amino, electron acceptor groups selected from cyano, sulphonic, nitro, or amide; R1 is an optionally substituted phenyl, benzyl or cyclohexyl group; R2 is selected from amino, substituted amino or guanidino groups, Z is a saturated or unsaturated C1-5 hydrocarbon chain, and salts thereof. A process for their preparation and compositions containing them are also described. The Compounds are either agonists or antagonists of a specific adenosine receptor or a number of adenosine receptors and have usefulness for the treatment of inflammation, arthritic conditions, rheumatoid arthritis, osteoarthritis, mental disorders, or for inducing central nerve regeneration.