Minor acetylated metabolites from Euphrasia rostkoviana. Natural and synthetic acetylated derivatives of rutin.

The phenylethanoids rostkovianoside, 6′-O-acetylcrassifolioside and the flavonoid rutin 3‴-acetate, were isolated from the methanolic extract of the aerial parts of Euphrasia rostkoviana Hayne. The structures of these previously undescribed compounds were elucidated by interpretation of spectroscopic data. The acetylation of rutin was also carried out and four ester derivatives were spectroscopically characterized. Finally, a chromatographic method was established to easily identify the acetylated position. [ABSTRACT FROM AUTHOR]