Antagonism of the adenosine A2A receptor offers great promise in the treatment of Parkinson's disease. Employing the known pyrazolo [4, 3-e]-1, 2, 4-triazolo [1, 5-c] pyrimidine A2A antagonist SCH 58261 as a starting point, we identified the potent and selective (vs. A1) antagonist 11h, orally active in the rat haloperidol-induced catalepsy model. We further optimized this lead to the methoxyethoxyethyl ether 12a (SCH 420814), ...