Synthesis of dihydrodehydrodiconiferyl alcohol and derivatives through intramolecular C–H insertion

Complete assignments of 1H and 13C NMR data of three new dihydrophenanthrofurans from Pleione yunnanensis

“…[11] NOE correlation between H-2 and H-3 was also not reliable for the determination of the relative configuration, either. [12] The determination of the relative conformation of compound 1 was based on a selective 1D NOE experiment. Irradiation of H-2 caused significant enhancements of H-1 , which ambiguously suggest a trans orientation of H-2 and H-3.…”

Neolignans and Caffeoyl Derivatives from Selaginella moellendorffii

“…-Compound 1 1 ) was obtained as an amorphous solid with an m/z of 441.1518 ([M þ Na] þ ) by HR-ESI-MS, leading us to assign it a molecular formula C 22 ). In the 13 C-NMR spectrum of 1 (Table 1) Table 1) with those of known neolignans revealed that compound 1 is a dihydrobenzofuran neolignan with oxidation of C(9') and methoxy substituentes at C(3), C(3'), C(5), and C(9') [9] [10], which was confirmed by the HMBCs of MeOÀC(3,5)/C(3,5), MeO-C(3')/C(3'), and MeO-C(9')/C(9') ( Fig.). The relative configuration of HÀC (7) and HÀC(8) was assigned as trans by the ROESY correlations of HÀC(7)/CH 2 (9); J values are useless to distinguish cis/trans diastereoisomers of the dihydrobenzofuran neolignans [9].…”

“…54 in the trans isomers and at d ca. 49 in the cis ones [9] [11], is a reliable criterion to distinguish both diastereoisomers. The chemical shift of C(8) (d 53.7) in 1 also suggested the relative trans-configuration of HÀC (7) Table 1) were very similar to those of 1, except for the signals of the side chain at 1 at d(C) 30.6 (t, C(7')), 36.0 (t, C(8')), 173.7 (s, C(9')), and 51.5 (q, MeOÀC(9')) which were replaced by those of 2 at d(C) 146.8 (d, C(7')), 116.4 (d, C(8')), and 170.9 (s, C(9')), implying that C(7') and C(8') were dehydrogenated and the carboxyl group (C(9')) was not esterified in 2.…”

Lignan derivatives from Selaginella tamariscina and their nitric oxide inhibitory effects in LPS-stimulated RAW 264.7 cells

“…The chemical shifts for C-7 (δ C 90.2) and C-8 (δ C 54.7) were similar to those reported for the compound in 2R,3S form. 18,19 The configurations for C-7 and C-8 were further were also isolated and identified as (2R,3S)-dihydro-2-(3,5-dimethoxy-4-hydroxyphenyl)-7-methoxy-5-acetyl-benzofuran (5) 16 and moellenoside B (6), 22 based on comparisons with spectroscopic data obtained from the literature (see Fig. 1).…”