1) Synthetic opioid 
Azaprocin is a drug which is an opioid analgesic with approximately 10x the potency of morphine, and a fast onset and short duration of action. It was discovered in 1963, but has never been marketed. The derivative substituted on the phenyl ring with a p-nitro group is more potent than the parent compound, around 25x the potency of morphine. The r...