The role of hygrine in the biosynthesis of cuscohygrine and hyoscyamine

Recent Developments in the Biosynthesis of the Tropane Alkaloids1

“…Hygrine (33) derivedfrom [5-14Clornithine was labeled equally at its C-2 and C-5 positions (ii). Earlier work (10) in which the unsymmetrical incorporation of ornithine into hygrine was reported has been shown to be invalid (ii). The cuscohygrine (34) isolated from Ery-throxylum coca plants which were fed [5-14C]ornithine was also labeled symmetrically in its pyrrolidine rings.…”

“…Others, such as cinnamic acid and benzoic acid, are more widespread in nature and are found in other types of natural products. 1 -methy1-2-pyrroline (31) which is in equilibrium with 30, The iminium salt 30 is also a precursor of the N-methylpyrrolidine rings of nicotine (32) (8, 9), hygrine (33) (10,11), and cuscohygrine (34) (12) as well as hyoscyamine and other tropane alkaloids. The iminium salt is formed by the cyclization of 4-methylaminobutanal (26) via the carbinolamine, 2-hydroxy-I -methylpyrrolidine (29).…”

“…Labeled hygrine served as a precursor of the tropine moiety of hyoscyamine and other tropane alkaloids (10,36,(63)(64)(65). In Datura innozia the (2R)-hygrine (50, depicted in Fig.…”

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“…1 -methy1-2-pyrroline (31) which is in equilibrium with 30, The iminium salt 30 is also a precursor of the N-methylpyrrolidine rings of nicotine (32) (8, 9), hygrine (33) (10,11), and cuscohygrine (34) (12) as well as hyoscyamine and other tropane alkaloids. The iminium salt is formed by the cyclization of 4-methylaminobutanal (26) via the carbinolamine, 2-hydroxy-I -methylpyrrolidine (29).…”

The application of root cultures to problems of biological chemistry

“…Certainly, 62 occurs in root cultures of Datura 81 and many other tropane-alkaloidproducing species. 87,88 When (R,S)-[N-methyl-14 C,2 -14 C]-62 was fed to Datura stramonium plants, 89 incorporation into 59 of intact precursor was reported. Crucially, incorporation was found 90 to be stereoselective, (2R)-[2 -14 C]-62 showing a 2.5 to 10-fold greater incorporation into the tropane alkaloids in Datura innoxia plants than (2S)-[2 -14 C]-62.…”