Thebaine (1) reacts reversibly with various nitroso-arenes to form cyclo-adducts by 1,4-addition of the nitroso-group to the conjugated diene system of the alkaloid. Adducts (2) of thebaine with nitrosobenzene and with 4-chloro-, 4-methyl-, 3-methoxy-, and 4-nitro-nitrosobenzene have been prepared in good yield. The adduct with nitrosobenzene was hydrolysed by hydrochloric acid to give 14β-(N-hydroxyphenylamino)codeinone (3; Ar = Ph) in high yield. Catalytic hydrogenation of this derivative afforded 7,8-dihydro-14β- phenylaminocodeinone (4). 14β-(N-Hydroxyphenylamino)codeinone rearranged readily in alkaline solution to give the phenol, 5,O-dihydro-5β,14β- (N-phenylepoxyimino)codeinone (5).
