Isolation of two unusual tetrahydroisoquinoline-monoterpene glucosides from alangium lamarckii as possible intermediates in the non-enzymatic formation of alangimarine from alangiside

Article abstract of DOI:10.3987/COM-97-8069

From the fruits of Alangium lamarckii, two new glucosides (3) and (4), which possessed unusual structures different from any known tetrahydroisoquinoline-monoterpene glucosides, have been isolated. Their structures were determined on the basis of spectroscopic and chemical methods. These same glucosides were also obtained by storage of alangiside (2) in MeOH for a prolonged period and glucoside (4) was further converted to alangimarine (1), a benzopyridoquinolizine alkaloid from this plant, by the usual treatment for isolation of alkaloids, suggesting the possibility of non-enzymatic formation of alangimarine (I) from alangiside (2) via the isolated glucosides (3) and (4).