Thebaine Rearrangements: Nonclassical D Ring Migrations

Article abstract of DOI:10.1021/jo00193a005

3,6-Dimethoxy-4-acetoxy-5-<2-(N-methylacetamido)ethyl>phenanthrene (3) and its isomer 3,6-dimethoxy-4-acetoxy-8-<2-(N-methylacetamido)ehyl>phenanthrene (4) have been detected as manufacturing byproducts at trace levels in illicit heroin.These compounds are novel rearrangement products obtained by the action of acetic anhydride (Ac2O) on thebaine (1).The syntheses of 3 and 4 from 1 proceed via the intermediate Δ^5,7,9(14)-N-acetyldesthebaine (2).Structural characterization and optimization of synthetic conditions for 3 and 4 are described.A brief discussion is also giving concerning other neutral products of 1 obtained under Ac2O conditions.