Dimeric aporphinoids

A study of three Berberis species, namely B. orthobotrys, B. calliobotrys, and B. zabeliana, has yielded four new aporphine dimers, i.e. chitraline (56), 1-O-methylpakistanine (57),67,68 kalashine (58),68,69 and khyberine (59).70 Kalashine and khyberine are the first aporphine-benzylisoquinoline dimers incorporating a diaryl ether terminal at C-ll of the aporphine moiety. 

A careful study of the dienone-phenol rearrangement in vitro of pakistanamine (60), which is the sole proaporphine-benzylisoquinoline alkaloid presently known, 

Northalicarpine (61), which is present in Thalictrum revolution, is the first known noraporphine-benzylisoquinoline dimer.29 Berberis orthobotris has also furnished two known dimeric alkaloids, pakistanamine (60) and pakistanine.67 Thalicarpine has been re-isolated from Thalictrum alpinum,42 Cancer patients showed no objective response when treated with this alkaloid.71 

A very useful complete listing of all proaporphine- and aporphine-benzyl-isoquinoline dimers, as well as aporphine-pavine dimers, together with their physical constants, has appeared.  

The known proaporphine-benzylisoquinoline pakistanamine has been found to be the main alkaloid in the seeds of Berberis julianae (Berberidaceae).  

A review has appeared dealing with the microbial transformations of natural anti-tumour agents, including thalicarpine.  

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H. Guinaudeau, M. Leboeuf, and A. Cav6, J. Nat. Prod. 47,565 (1984). Dimeric aporphinoid alkaloids. Cites 23 new dimeric alkaloids and 8 related synthetic derivatives for 1979-1984 48 references. 

M. Shamma and H. Guinaudeau, Tetrahedron 40, 479S (1984). Biosynthesis of aporphinoid alkaloids. In addition to monomeric alkaloids, discusses proaporphine- and aporphine-benzyliso-quinoline dimers, dimeric oxidized aporphines, and types derived by catabolism of benzyliso-quinoline-derived dimers. 

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... 

Other types of dimers have been found recently in another Annonaceous species. Four bisaporphinoids have been isolated from Polyalthia cauliflora var. beccarii (Jossang et al. 1982). Three of these are beccapolinium (91), beccapoline (92), and beccapolydione (93). These alkaloids are characterized by a carbon-carbon bond between carbon atoms 4 and 7 of two aporphinoid moieties (Fig. 20). 

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