Stereostructures of two biflavanones from Stellera chamaejasme L.

Antimitotic and Antifungal C-3/C-3"-Biflavanones from Stellera chamaejasme

“…4) However, the chirality of C-3/C-3Љ remains uncertain, like those known biflavanones. 1,[4][5][6] In previous studies, the meso-form and d-or l-form biflavanones as 2 and chamaejasmenin B were commonly reported, such as isochamaejasmin (mesoform) 7) and chamaejasmenin (l-form), 8) isoneochamaejasmin A (meso-form) 9) and neochamaejasmin A (d-form) 5) isolated from the same plant. The structure of 2 was thus established to be [3,3Ј-Bi-4H-1-benzopyran]-4,4Ј-dione, 2,2Ј,3,3Ј-tetrahydro-5,5Ј,7Ј,7-tetrahydroxy-2,2Ј-bis(4-methoxyphenyl)-(meso), and named isochamaejasmenin B.…”

Antifungal derivatives from Piper mollicomum and P. lhotzkyanum (Piperaceae)

“…These signals associated to multiplet at δ 7.1 -7.3 (5H) and a peak at δ 5.91 (2H) suggested the occurrence of a dihydrochalcone. Signals referring to carbonyl group at δ 204.5 (C=O), aromatic group at δ 94.5 -165.6 despite of aliphatic carbons at δ 45.6 (CH 2 ), 30.5 (CH 2 ) and 55.5 (CH 3 ), in the 13 C NMR spectra (BBD and DEPT 135°), confirms the structural arrangement of 5 as 2',6'-dihydroxy-4'-methoxydihydrochalcone. 10 In the both 1 H NMR spectra of 6 and 7 were observed AB systems at δ 6.95 (d, J = 8.7 Hz) and 7.37 (d, J = 8.7 Hz), characteristic of para-dissustituted aromatic ring, and two doublets at δ 6.02 (J = 2.4 Hz, 1H) and 6.10 (J = 2.4 Hz, 1H) indicative of a 1,2,3,5-tetrassubstituted aromatic ring.…”

“…The remaining NMR data, in association to LREIMS, which showed the molecular ion-peak at m/z 234, suggested an additional hydroxyl group. Since the aromatic hydrogens were positioned in meta, this group was attached at C-8, which was confirmed by signal at δ 143.4 (C) in the 13 C NMR spectra, characteristic of an aromatic carbinolic carbon. Therefore, this compound was identified as methyl 8-hydroxy-2,2-dimethyl-2H-chromene-6-carboxylate.…”

“…1 H and 13 C NMR spectra (BBD -broad band decoupled and DEPT 135° -distortionless enhancement by polarization transfer) were measured at 300 and 75 MHz, respectively, on a Bruker model DPX-300 spectrometer with samples dissolved in CDCl 3 (Aldrich). TMS was employed as internal standard: chemical shifts were recorded in d (ppm) and coupling constants (J) in Hz.…”

A New Dicoumarinyl Ether from the Roots of Stellera chamaejasme L

“…Previous phytochemical studies of S. chamaejasme showed the presence of groups of biflavonoids, diterpenes, lignans, and coumarins [3][4][5][6][7][8][9][10][11][12]. In our continuous studies on the chemical constituents of S. chamaejasme, a new bicoumarin, 3-hydroxy-6-methoxy-7,7'-dicoumarinyl ether (1, Figure 1) was isolated, together with the known coumarin umbelliferone (2).…”