Benzylisoquinoline alkaloids benzophenanthridine

The use of u.v. spectroscopy to determine the nature and position of methoxy-and methylenedioxy-substituted aromatic rings has been systematically applied to protoberberine, protopine, benzophenanthridine, and proto-ochotensimine alkaloids.51 I.r. spectra of examples of almost all subgroups of benzylisoquinoline alkaloids, including emetine, have been recorded and characteristic bands in the 1800—1480 cm-1 region have been used to identify a particular subgroup.52... 

Several types of data based on feeding experiments, isolation of intermediates and in vivo NMR experiments, indicate that norcoclaurine (23) serves as a precursor to both coclaurine (24) and (S)-reticuline (20) (Stadler et al., 1987, 1989), and that (5)-coclaurine (24) serves as a specific precursor to other classes of benzylisoquinoline alkaloids, such as the protoberberines, benzophenanthridines, and morphinandie-nones, as well as for pavine and benzophenanthridine alkaloids in intact plants (Stadler et al., 1987, 1989). The five enzymes involved in the conversion of dopamine and 4-hydroxyphenylacetaldehyde (19) to (S)-reticuline (20) have been elucidated (Frenzel and Zenk, 1990b). 

Fig. 3 Primary precnrsor-end product relationships in alkaloid biosynthesis. Color codes blue, terpene indole alkaloids green, benzophenanthridine alkaloids gray, benzylisoquinoline alkaloids red, quinolizi-dine alkaloids yellow, pyridine alkaloids pink, tropane alkaloids...

S)-(+)-reticuline (20) and orientaline (25). The alkaloids of the Papaveraceae and Fumariaceae can be subdivided into several constitutional types (Fig. 3), viz., simple isoquinolines, benzylisoquinolines, pavines, isopavines, cularines, proaporphines, aporphines, promorphinanes, morphinanes, protoberberines, retroprotoberberines, secoberbines, benzophenanthridines, protopines, phthali-deisoquinolines, secophthalideisoquinolines, indenobenzazepines, spirobenzyl-isoquinolines, and rhoeadines. 

The following groups of alkaloids occur in the plant family of the Papaveraceae benzylisoquinoline, cularine, aporphine, proaporphine, morphine, protoberberine, protopine, narceine, benzophenanthridine, phthalide-isoquinoline, rhoeadine, papaverrubine, pavine, isopavine and ochotensimine. Many of these alkaloid groups are formed by one genus only, whereas others occur in many genera and even in plants of other families. Alkaloids of all these groups must thus be taken into considera-... 

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