The present invention relates to compounds of formula I ##STR00001## wherein R.sup.1 and R.sup.2 are described hereinbelow. These compounds have high affinity to A.sub.2A receptors and good selectivity to A.sub.1 and A.sub.3 receptors. These compounds are useful, inter alia, in the treatment of Alzheimer's disease, depression, Parkinson's disease and ADHD.