Novel compounds which selectively bind to the ?-opioid receptor have been designed. These compounds have greater selectivity, improved water (blood) solubility, and enhanced therapeutic value as analgesics. Because agonists with selectivity for the ?-opioid receptor have shown promise in providing enhanced analgesis without the addictive properties, the compounds of the present invention are better than morphine, naltrindole (NTI), spiroindanyloxymorphone (SIOM), and other known ?-opioid receptor selectors as analgesics.