Stylopine methochloride

Additional results are that (-)-(5)-scoulerine (68) is a precursor for san-guinarine (77) and chelerythrine (78) and labelled (-)-(5)-stylopine (71) is incorporated into coptisine (72). [N-methyl8- H]Stylopine methochloride [as (70)] afforded chelidonine (76) and protopine (73) essentially without change in isotope ratio and must thus be considered as implicated on the pathway to both alkaloids. (The same conclusion for protopine has been reached independently. ) On the other hand radioactive nandinine (79) failed to label chelidonine, stylopine, or protopine, suggesting that the alternative (69) may be an intermediate instead. In agreement with other work (5)-reticuline (67) and (5)-scoulerine (68) were much better precursors than the i -isomers for protopine (73), and incorporation of (68) resulted in complete loss of tritium label from C-14. Allocryptopine (81) was well labelled by radioactive isocorypalmine (82) (which also serves as a precursor for narcotine see below). The combined results lead to the pathways shown in Scheme 3. 

Tani and Tagahara also studied the biosynthesis of rhoeadine and reported that in P. rhoeas this alkaloid arises from a-stylopine methochloride (58n) via protopine. jS-Stylopine methochloride does not participate in this biosynthesis (740). 

The biosynthesis proceeds from reticuline via proto-betberine derivatives, e.g., stylopine methochloride. lit. Mothes etal., p. 226-230 Prog. Bot. 51, 113-133 (1980). 

Stylopine methochloride is incorporated into the biogenetic scheme. 

Protopine.—It is known that protopine (94) is elaborated in vivo along a route which involves ( + )-reticuline (82) ° and (-)-scoulerine (91) and, probably, stylopine (92) 110 quaternary salt (93) is also to be included in the pathway, a conclusion which follows from the incorporation into protopine (94), in Corydalis incisa, of [N-Me- Cjtetrahydrocoptisine methochloride [as (93)] without loss of the N-methyl group. " [Label from this salt was not incorporated into corynoline (95).]... 

The naturally occurring quaternary tetrahydroprotoberberine types of alkaloids are predominantly in the a-form, except for the / -2-canadine methochloride. The stereochemistry of stylopine methohydroxide remains undefined (500). 

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