Phenethylamine and Isoquinoline Alkaloids

A stimulating review on unsolved problems in isoquinoline biosynthesis has been published.  

The seminal ideas relating to the oxidative coupling of phenols have found very widespread application, and yet the actual mechanism of coupling in vivo remains obscure. In new work, it has been found that extracts of Papaver somniferum which had peroxidase activity were unable to catalyse the conversion, by phenol oxidative coupling, of reticuline into salutaridine. 

All of the twenty-seven known spirobenzylisoquinoline alkaloids, e.g. (20), contain a methylenedioxy-group on ring D. 

It has been suggested that the formation of these groups from an ortho-methoxy-phenol is encouraged by steric compression around a 

C-9 roethoxy-substituent which is relieved very substantially upon 

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