U-47700 CAS 82657-23-6

U-47700 CAS 82657-23-6

U-47700 is an opioid analgesic drug developed by a team at Upjohn in the 1970s.U-47700 was derived from an earlier opioid AH-7921. U-47700 is selective for the μ-opioid receptor with a Kd value of 5.3 nM compared to 910 nM for the κ-opioid receptor and has around 7.5 x the potency of morphine in animal models.

U-47700 is the result of a great deal of work elucidating the quantitative structure–activity relationship of the scaffold. The team looked for the key moieties which gave the greatest activity.Upjohn posted over a dozen patents on related compounds, each optimizing one moietyuntil they discovered that U-47700 was the most active.

U-47700 became the lead compound of selective kappa-opioid receptor ligands such as U-50488 (containing a single methylene spacer difference) and U-69,593, which share very similar structures. Its structure led to other chemists experimenting with it to see if rigid analogues would retain activity.Although not used medically, the selective kappa ligands are used in research.