Over the course of our research, no MC2R antagonist chemical structures were available in the scientific literature. A US patent (WO2019236699A1) previously disclosed the only publicly available MC2R antagonists. In the final stages of our study, Kim and coworkers published CRN04894, an MC2R inhibitor that advanced to phase I . These antagonists and those from the patent have undergone further chemical optimization to enhance potency and reduce ADMET liabilities. The patented compounds all contain an arylpiperazine functional group fused to at least one additional aromatic ring (Fig ). This motif is common among GPCR antagonists . In contrast, our catalog compounds ATMW-1-12 represent structurally diverse starting points that do not contain the arylpiperazine moiety and provide new regions of chemical space to explore and optimize, differentiated from existing MCXR and other GPCR antagonists.