Chemical Constituents of Rhododendron lepidotum
Two new coumarin glycosides, 7-O-β-D-glucopyranosyl-8-methoxybenzopyranone (1) and 7-hydroxy-8-O-β-glycosylbenzopyranone ((2), are reported along with the isolation of 7,8-dihydroxy coumarin (daphnetin) from Rhododendron lepidotum (aerial part).
New natural compounds from Rhododendron lepidotum
Phytochemical investigation of the aerial parts of Rhododendron lepidotum yielded 8-[2′,6′-dimethoxy-4′-(1″,2″,3″-trihydroxy-propyl)-phenyl]-7-hydroxy benzopyranone (1), 3-O-β-d-glycopyranosyl betulinic amide (2) and 8-hydroxy-7,7′-oxydicoumarin (4) and five known compounds. Among the known molecules, betulinic amide (3) was earlier reported as a semi-synthetic product. The structures of new molecules 1, 2 and 4 were elucidated on the basis of extensive spectroscopic investigations (1D NMR, 2D NMR and mass spectrometry).
Chemical and Chemotaxonomical Studies of Filices. LXI. Chemical Studies on the Constituents of Pronephrium triphyllum HOLLT.
From the fronds of Pronephrium triphyllum HOLLT., three new glycosides, named triphyllins A, B and C, were isolated. Their structures were determined as (2R, 4S)-5, 7-di-β-D-glucosyloxy-6-hydroxymethyl-4'-methoxy-8-methylflavan-4-ol, (2R, 4S)-5, 7-di-β-D-glucosyloxy-4'-hydroxy-6-hydroxymethyl-8-methylflavan-4-ol and (2S)-7-β-D-glucosyloxy-5-hydroxy-4'-methoxy-6-methoxymethyl-8-methylflavanone, respectively, on the basis of spectral data and chemical correlations.