A recent study reported that the GPR139 agonist TC-O 9311 (structurally identical to compound 1a used in this study) protected primary mesencephalic dopamine neurons against 1-methyl-4-phenylpyridinium (MPP+)-mediated degeneration, indicating a potential role of GPR139 in neuroprotection and Parkinson’s disease (Bayer Andersen et al., 2016). Here, GPR139 is linked to Parkinson disease.