Biogenesis and Biosynthesis

The general role played by strictosidine (151) (Fig. 8) in the biosynthesis of all monoterpenoid indole alkaloids is firmly established (220-224). In the biogenetic formation of sarpagine (and ajmaline) alkaloids, the van Tamelen proposal (201,202) has been generally accepted (213,222,223), that is, that formation of a bond between C-5 and C-16 in the intermediate 4,5- 

The main argument advanced by Lounasmaa and Hanhinen (203) in rejecting the van Tamelan proposal (201,202) was that the shortest possible distance between the reactive sites C-5 and C-16 in intermediate 152 is about 2.70 A (Fig. 9), which is far too large to permit bond formation between C-5 and C-16. In the alternative proposal where the bond formation takes place before the D-ring formation, the minimal distance between the reactive sites C-5 and C-16 in intermediate 155 is about 1.50 A, which is suitable for bond formation (Fig. 9). 

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THE BIOSYNTHESIS AND BIOGENESIS OF LIGNIN IN PLANT CELL WALLS... 

Subsequent to the appearance of Volume VI of this series, a number of reviews on the tropane alkaloids have appeared, dealing with chemistry (i, 2), biosynthesis and biogenesis (3, 4), and pharmacological activity as a function of structure (5, 6). 

Structures of Representative Alkaloids Biosynthesis and Biogenesis Total Synthesis... 

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