Aporphine-benzylisoquinoline dimers oxidation

The year under review has witnessed the isolation and structural elucidation of no less than nine new aporphines, as well as of five aporphine-benzylisoquinoline dimers. Two of these five aporphine-benzylisoquinolines, namely kalashine and khyberine, are the first such dimers known to be substituted at C-l 1 of the aporphine moiety. Thallium(m) trifluoroacetate is an oxidizing agent which effects the cyclization of tetrahydrobenzylisoquinolines to aporphines in satisfactory yields.1 A listing of aporphinoid alkaloids has appeared.2... 

New aporphine-benzylisoquinoline dimers are ( + )-thalirevolutine (38), (-1-)-thalirevoline (39), (-H )-thalilutidine (40), and (-H )-thalilutine (41), all present in Thalictrum revolutum (Ranunculaceae) while (-I- )-thaliadanine (42) is found in Thalictrum minus Race B. Another new alkaloid is thaliadine (43), also located in T. minus Race Thaliadine must be an oxidation product of an aporphine-benzylisoquinoline alkaloid. 

A relevant and very recent development is the isolation and characterization by Beal, Doskotch, and co-workers, of the new alkaloid ( + )-thaliadine from Thalictrum minus L. race B (Ranunculaceae). This alkaloid is accompanied in the plant by such aporphine-benzylisoquinoline dimers as (-h)-adiantifoline, (+)-desmethyladiantifoline, and (-h)-thaliadanine (Sec. 12.1), and must be formed from their oxidative degradation. ... 

It has been indicated that isoquinolone alkaloids originate in plants from oxidation of simple benzylisoquinolines. A parallel assumption is that hernan-daline is formed by oxidation of a thalicarpine-type aporphine-benzyliso-quinoline. It is self-evident from the structure of baluchistanamine that in vivo oxidation of an oxyacanthine type alkaloid to an isoquinolone-benzyliso-quinoline dimer, as well as of a simple monomeric benzylisoquinoline to an isoquinolone, is an intrinsic feature of the alkaloidal catabolic process within B. baluchistanica. 

---