Codeinone prepn. from thebaine - by reacting with a halohydric acid in anhydrous medium in the presence of a catalyst, e.g. iodine

摘要

Codeinone (I) is prepd. from thebaine (II) by reacting it with a halohydric acid in an anti-medium in the presence of a catalyst at >=10 degrees C, hydrolysing in an alkaline medium and extracting (I). Yields of up to 95% are obtd. Pref. (II) dissolved in CH2Cl2 is treated, in the presence of I2, with HBr in di-n-butyl ether, hydrolysing in an alkaline medium contg. NaHCO3, extracting with CH2Cl2 and removing the solvent to obtain (I).