Reactions with Alkylating and Acylating Agents

Dimeric protoberberinium salts have been obtained by reaction of dihydro-protoberberines with formaldehyde, most probably by the mechanism indicated below 

The iV-methyldihydroprotoberberine salt 49, derived from the ditosylate 48 of narcotinediol, upon heating with sodium iodide and acetic anhydride afforded the quaternary salt 50. A mechanism is suggested below 

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