7,8-DEHYDROMETATHEBAINONE METHOPERCHLORATE PRIMARY PRODUCT OF ACID TREATMENT OF THEBAINE METHOSALTS

Reaction of concentrated acids with salts of N-methylthebaine at room temperature leads to the formation of the previously unreported 7,8-dehydrometathebainone (2), isolated as its methoperchlorate. In the presence of acids 2 adds methanol or ethanol giving 8-methoxy- or 8-ethoxy-metathebainone methoperchlorate (10a and 10c). Controlled Hofmann degradation of 4-O-methyl-7,8-dehydrometathebainone methoperchlorate (9b) yields the corresponding, deeply yellow methine (11a), giving a colourless rearrangement product with alkali. © 1968 Springer-Verlag.