The Use of Lead Tetraacetate Hydroxylation at

Oxidation of codamine with lead tetraacetate and subsequent treatment with acetic anhydride and concentrated sulfuric acid is known to generate 4-acetoxy-O-acetylthaliporphine and 0-acetylthaliporphine. It has now been authoritatively reported that lead tetraacetate oxidation of thaliporphine (3) itself affords 4j8-acetoxythaliporphine whose hydrolysis and 0-methylation produces cataline in 87% overall yield. Alternatively, reaction of 4j8-acetoxy-thaliporphine with methanol leads to 4j8-methoxythaliporphine, probably through the intermediacy of a quinone methide.  

In a new variation of this series of reactions, treatment of the initial quinol acetate, obtained from lead tetraacetate oxidation of codamine, with TFA resulted in a substantial increase in the yield of the corresponding aporphine, namely thaliporphine (3), while no C-4 oxygenated aporphine could be detected.  

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