Two additional 1,9-diarylnonanoid 3-glucosides from Erica cinerea among which an unusual α-dione in conformational equilibrium

The acetone extract of Erica cinerea fresh aerial parts afforded the new 1,9-diarylnonanoid 3-O-β-d-glucopyranosides 5 and 6. Very uncommon in the plant kingdom, the α-alkadione structure, was found as an indivisible mixture of the s-trans and s-cis conformers.