This invention relates to compounds of formula I ##STR00001## wherein R.sup.1 and R.sup.2 are defined herein, or a pharmaceutically acceptable salt thereof. It has been found that the compounds of formula I are adenosine receptor ligands with good affinity to the A.sub.2A-receptor and a high selectivity to the A.sub.1- and A.sub.3 receptors. These compounds are useful, inter alia, in treatment of Alzheimer's disease, depression, Parkinson's disease and ADHD.