“…On a biosynthetic basis, H-5 was assigned with a pseudo-β-axial configuration. 20,21 The coupling constant of H-1 (5.5 Hz) showed that it is R-oriented and the glucosyl moiety is in the β-position, similar to those recorded in the previous literature. 18,19 Subsequently, the β-orientation of H-9 was confirmed by the NOE correlation and coupling constants.…”
supporting
confidence: 86%
“…The stereochemistry of C-1, C-5, and C-9 in 1 was determined by analysis of the 1 H and 13 C NMR data, the NOESY correlations (Figure ), and inspection of a computer-generated model. On a biosynthetic basis, H-5 was assigned with a pseudo-β-axial configuration. , The coupling constant of H-1 (5.5 Hz) showed that it is α-oriented and the glucosyl moiety is in the β-position, similar to those recorded in the previous literature. , Subsequently, the β-orientation of H-9 was confirmed by the NOE correlation and coupling constants. 1 Key NOESY correlations of 1 and 2 .…”
A new secoiridoid glycoside, hydrachoside A (1), along with 14 known compounds, was isolated from the leaves of Hydrangea chinensis. The absolute stereochemistry of the side chain attached to C-15 on the secoiridoid glycoside hydrangenoside E (2) was determined by NMR spectral analysis. The structures of compounds 1 and 2 were elucidated on the basis of spectral data. The previously reported structure, hydrachine A (3), was revised as its epimer, (-)-neodichroine (4), a new compound.
“…On a biosynthetic basis, H-5 was assigned with a pseudo-β-axial configuration. 20,21 The coupling constant of H-1 (5.5 Hz) showed that it is R-oriented and the glucosyl moiety is in the β-position, similar to those recorded in the previous literature. 18,19 Subsequently, the β-orientation of H-9 was confirmed by the NOE correlation and coupling constants.…”
supporting
confidence: 86%
“…The stereochemistry of C-1, C-5, and C-9 in 1 was determined by analysis of the 1 H and 13 C NMR data, the NOESY correlations (Figure ), and inspection of a computer-generated model. On a biosynthetic basis, H-5 was assigned with a pseudo-β-axial configuration. , The coupling constant of H-1 (5.5 Hz) showed that it is α-oriented and the glucosyl moiety is in the β-position, similar to those recorded in the previous literature. , Subsequently, the β-orientation of H-9 was confirmed by the NOE correlation and coupling constants. 1 Key NOESY correlations of 1 and 2 .…”
A new secoiridoid glycoside, hydrachoside A (1), along with 14 known compounds, was isolated from the leaves of Hydrangea chinensis. The absolute stereochemistry of the side chain attached to C-15 on the secoiridoid glycoside hydrangenoside E (2) was determined by NMR spectral analysis. The structures of compounds 1 and 2 were elucidated on the basis of spectral data. The previously reported structure, hydrachine A (3), was revised as its epimer, (-)-neodichroine (4), a new compound.
“…Among them, six phenylethanoid glycosides (1-6) and fi ve iridoid glycosides (13-17) were obtained from this plant for the fi rst time. By comparing their MS and NMR data as well as the physical properties with the literature, their structures were identifi ed as 4″′-O-acetylverbascoside (1) (Kanchanapoom et al, 2002), verbascoside (also named kusaginin) (2) (Sakurai and Kato, 1983), cistanoside E (3) (Wu et al, 2004), martynoside (4) (Sasaki et al, 1989 ), leucosceptoside A (5) (Miyase et al, 1982), and 6″-O-acetyl-verbascoside (6) (Kanchanapoom et al, 2002), catalpol (13) (Oshio and Inouye, 1981), dihydrocatalpol (14) (Boros and Stermitz, 1990), 5,9-epi-7,8-didehydro-penstemoside (15) (Dinda et al, 2007a(Dinda et al, , 2007b, 5-hydroxy-8-epideoxyloganin (16) (Damtoft et al,1992), geniposide (17) (Ono et al, 2005). The molecular weights and chemical formulae of compounds 1 and 2 were deduced from HR-ESIMS.…”
Bioassay-guided fractionation of the antibacterial ethyl acetate-ethanol (50 : 50) extract obtained from the aerial parts of Penstemon centranthifolius led to the isolation of six phenylethanoid glycosides (1-6) and eleven iridoid glycosides (7-17). Their structures were determined on the basis of spectroscopic analysis and comparison with the literature. Among them, two phenylethanoid glycosides, 4'''-O-acetylverbascoside (1) and verbascoside (2), were found to show significant inhibition of the formation of bacterial biofilms by Escherichia coli UTI89. Compound 1 showed 77% biofilm inhibition at 2.5 microg/mL, and compound 2 showed 60% inhibition at 5 microg/mL.
“…Although 8-epi-deoxyloganin had previously been shown to be an excellent precursor of ( 67) and ( 68), it appears not to be on the main pathway. The early part of the pathway shown in Scheme 13 is also probably utilized for the biosynthesis of antirrhinoside (69) in Antirrhinum majux70 8-epi-Iridotrial (63) was a better precursor than its glucoside and 8-epi-deoxyloganic acid (64) was also well incorporated. 8-epi-Deoxyloganic acid is efficiently converted into the iridoid glycosides caryoptoside Scheme 16 (70) and lamalbid (71) and into the secoiridoid alboside B (72) in Lamium album.71 In addition, caryoptoside was shown to be a precursor of ( 71) and (72) (Scheme 14).…”
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