29 y/o M was complaining of the headache and collapsed abruptly. EMS was termed and resuscitation was unsuccessful. dimethylamino group drastically boosts the MOR affinity, as in U-47700. In contrast, embedding that very same standard nitrogen into a cyclic pyrrolidine ring tremendously enhances the KOR affinity, as in U-50488. MOR/KOR https://prosyntheticchems.com/product/u-48800/