Corysamine, tetrahydro

Corysamine, tetrahydro I 67 R2R3R9Ri0=OCH2O Corydalis dasyptera (Papaveraceae) 145... 

Further detail on the biosynthesis of corynoline (78) and related alkaloids is that (76) is a precursor for corynoline (78) and corycavine (77).64 In the latter case it was observed that the configurations at C-13 and C-14 in the precursor were unimportant and incorporation occurred via the metho-salt. Tetrahydro-corysamine (76) is closely related to corydaline, whose biosynthesis from tyrosine and methionine has been studied.66 The C-methyl group at C-13 was shown to arise from methionine and the mechanism suggested for the methylation involves... 

In a more recent study, and working with Corydalis incisa and Chelidonium majus, Takao and co-workers have demonstrated that only the cis B/C fused A -metho salts of tetrahydroprotoberberines such as stylopine, tetrahydro-corysamine, and mesotetrahydrocorysamine, are converted into the corresponding protopines, while the trans fused salts are inefficient precursors. ... 

Emde degradation on pyrolysis with selenium gave 2-methyl-6,7-methylenedioxynaphthalcne (V) therefore the position of the C-methyl group in corynoline is fixed (5). This is the position in which the C-niethyl group would be expected to occur if corysamine or its tetrahydro derivative is the biosynthetic intermediate in the synthesis of corynoline. This would be analogous to the in vivo transformation of stylopine into chelidonine (4). 

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