Synthesis and Pharmacological Evaluation of Aminothiazolomorphinans at the Mu and Kappa Opioid Receptors

Previous studies with aminothiazolomorphinans suggested that this class of opioid ligands may be useful as a potential pharmacotherapeutic to decrease drug abuse. Novel aminothiazole derivatives of cyclorphan were prepared to evaluate a series of aminothiazolomorphinans with, varying pharmacological properties at the kappa opioid receptor (KOR) and mu opioid receptor (MOR). This study was focused on exploring the regioisomeric analogs with the aminothiazole on the C-ring of the morphinan skeleton. Receptor binding and [S-35]GTP gamma S binding assays were used to characterize the affinity and pharmacological properties of the aminothiazolomorphinans. Intracranial self-stimulation (ICSS) was used to compare the effects of a representative aminothiazolomorphinan with the morphinan mixed-KOR/MOR agonist butorphan (MCL-101) on brain-stimulation reward.