SCH-442,416 is a highly selective adenosine A<sub>2a</sub> subtype receptor antagonist. It is widely used in its <sup>11</sup>C radiolabelled form to map the distribution of A<sub>2a</sub> receptors in the brain, where they are mainly found in the striatum, nucleus accumbens, and olfactory tubercle. Given its distribution in the brain, A<sub>2a</sub> receptors have been investigated for the treatment of various neurological disorders, and SCH-442,416 has shown promise in treatment of depression, Parkinson's disease, and catalepsy.