Prostratin C (1) isolated from Euphorbia prostrata, and praecoxins C (2) and D (3) isolated from Stachyurus praecox, were found to be hydrolyzable tannins having a depsidone-forming valoneoyl group as a constituent unit. The orientation of the valoneoyl group in praecoxins C and D as in the structures 2 and 3 was unequivocally proved by the 1H-13C long-range shift correlation spectrum of rugosin C (5) which was chemically correlated with praecoxin C.
|Number of pages||4|
|Publication status||Published - Jul 1 1990|
ASJC Scopus subject areas
- Analytical Chemistry
- Organic Chemistry