Ketones hydrobromination

A convenient synthesis of glaziovine proceeds from the dihydroproaporphine amuronine which is available by the Bernauer tricyclic ketone approach. Thus when amuronine was refluxed with 20-36% hydrochloric acid, O-demethylation occurred preferentially at C-1 to yield 11,12-dihydroglaziovine which was 0-acetylated, and then converted to glaziovine through bromination and de-hydrobromination. It should be mentioned here that preferential 0-demethyla-tion cannot be applied directly to a proaporphine since under such strongly... 

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