codeinone was additionally verified by X‐ray crystallography. Compounds 5a, 8, 11a, and 16 have been evaluated for their affinity at μ and κ opioid receptors in radioligand binding assays. Their ability to inhibit [3H]DAMGO binding at μ and [3H]U 69.593 binding at κreceptors, respectively as compared to codeine has been found to be lower.