BU72 is an extremely potent opioid used in pharmacological research.
Pharmacology
BU72 is an agonist for the μ-opioid receptor with exceptionally high binding affinity and potency, comparable to carfentanil.[1] It also has extremely high efficacy, giving a stronger maximal effect than the standard full agonistDAMGO.[2] In animal studies, it was found to be a potent analgesic, with a slow onset and long duration of action.[3][4]
Chemistry
BU72 was used to produce the first crystal structure of the active μ-opioid receptor,[1] and is now widely used to model the activation process.[5][6][7] The stereochemistry has recently been revised, with the phenyl group in the (R) configuration.[8][9] In the crystal structure, BU72 appears to bond to the receptor covalently,[10][11] but this seems not to occur in vivo, since the compound binds reversibly, and preventing bond formation has no effect on affinity.[1]
BU72 original proposed structure ((S)-phenyl epimer)
^Neilan CL, Husbands SM, Breeden S, Ko MC, Aceto MD, Lewis JW, et al. (September 2004). "Characterization of the complex morphinan derivative BU72 as a high efficacy, long-lasting mu-opioid receptor agonist". European Journal of Pharmacology. 499 (1–2): 107–116. doi:10.1016/j.ejphar.2004.07.097. PMID15363957.
^Sena DM, Cong X, Giorgetti A (March 2021). "Ligand based conformational space studies of the μ-opioid receptor". Biochimica et Biophysica Acta (BBA) - General Subjects. 1865 (3): 129838. doi:10.1016/j.bbagen.2020.129838. PMID33373630. S2CID229721515.
^Zou R, Wang X, Li S, Chan HS, Vogel H, Yuan S (2022). "The role of metal ions in G protein-coupled receptor signalling and drug discovery". WIREs Computational Molecular Science. 12 (2). doi:10.1002/wcms.1565. ISSN1759-0876.
^Husbands, S. M., Lewis, J. W. (December 1995). "Morphinan cyclic imines and pyrrolidines containing a constrained phenyl group: High affinity opioid agonists". Bioorganic & Medicinal Chemistry Letters. 5 (24): 2969–2974. doi:10.1016/0960-894X(95)00522-1.