Trioxygenated Coumarins

Formula M.p. Mi Solvent Plant Source(s) Leading References 

---

Such NA effects increasingly lead to problems in signal assignments with the number of substituents becoming higher, for example in 6,7,8-trioxygenated coumarins (80). Carbon atoms of the substituents themselves are affected as well (section 5)... 

The poor utilization of ferulic acid raises a point of interest. As mentioned above, there has long been evidence that scopoletin in tobacco arises from ferulic acid. However, this evidently cannot be the case in Agathosma, since scopoletin is well utilized to form puberulin, but ferulic acid is not. It may be that scopoletin, like the other di- and trioxygenated coumarins thus far studied, originates via umbelliferone in most species, and that the picture in tobacco is exceptional. 

Coumarins trioxygenated on the benzene ring occur naturally in three patterns 5,6,7-, 5,7,8- and 6,7,8-. 

---