New Lignan Glucosides from the Stems of Tinospora sinensis

Abstract

Two new lignan glucosides, tinosposides A and B (1 and 2), were isolated from the stems of Tinospora sinensis collected in Hainan Island, China. Their structures were elucidated on the basis of spectroscopic analysis and chemical evidence.

Two New Lignan Glycosides from Saussurea laniceps

“…Trivial atom numbering. tinosposide B [8]. The latter was also supported by the ROESY correlation between HÀC(7') and H b ÀC(9').…”

“…The spectral data mentioned above together with HMBC correlations (Fig. ), suggested 1 to possess a C(7)ÀOÀC(9') tetrahydrofuran lignan skeleton, similar to those of tinosposide B [8] and tanegool [9]. In the HMBC, two oxygenated CH groups at d(C) 86.3 and 77. assigned to C(7) and C(7'), respectively, by the HMBC correlations of HÀC(2) and HÀC(6) to C(7), and HÀC(2') and HÀC(6') to C(7').…”

“…5.5) [10], and this was confirmed by the ROESY correlation between HÀC(7) and CH 2 (9). Arbitrarily assuming a b-configuration of HÀC (8), the correlations between HÀC(8') and CH 2 (9), and between HÀC(7') and H b ÀC(9') indicated that HÀC (7) and HÀC(8') were both in a-orientation. The relative configuration at C(7') was determined by comparison of the chemical shift and coupling constant of HÀC(7') with those of Table. 1 H-and 13 C-NMR Data of 1 and 2 a ).…”

“…HMBC Correlations of CH 2 (9') to C(7), C(8'), and C(8) then completely established the tetrahydrofuran ring skeleton. The HMBC correlations of CH 2 (9) to C(7) and C(8') located the hydroxymethyl group at C (8). The connection between C(7') and C(8') was suggested by the HMBC correlation between HÀC(8') and C(7').…”

Two New Stereoisomers of Tetrahydrofuranoid Lignans from the Flower Buds of <i>Magnolia fargesii</i>

“…On the other hand, to solve the absolute configurations at C-8Ј, C-8, and C-7 in 1, the Circular Dichroism spectrum of 1 was compared with that of tanegool. 20,21) The CD spectrum of compound 1 ([a] D ϩ25.4°, CHCl 3 ) showed the positive absorption peaks at 230 and 280 nm, which were identical with the known compound tanegool ([a] D ϩ12.0°, CHCl 3 ). Thus, the structure of compound 1 was determined to be the new isomer, 7S,8R,7ЈS,8ЈR-3,4,3Ј,4Ј-tetramethoxy-9,7Ј-dihydroxy-8.8Ј,7.O.9Ј-lignan (1).…”