A Rapid, Large-Scale Synthesis of a Potent Cholecystokinin (CCK) 1R Receptor Agonist

The development of a scalable synthesis of a potent cholecystokinin (CCK) 1R receptor agonist is described. The focus on a rapid short-term delivery rather than longer-term development allowed for the preparation of multihundred gram quantities to support aggressive timelines and evaluate safety and pharmacological studies. Key improvements involved streamlining the preparation of imidazole acid 7 and discovery of a more efficient preparation of naphthyl piperazine fragment 23, including an improved preparation of 3-bromonaphthallic anhydride 16.