The Syntheses and Absolute Configurations of Nellionol and 5-Dehydronellionol

Abstract

To determine the absolute configurations of C-15 in natural nellionol and 5-dehydronellionol, (15R)-8,11,13-abietatriene-12,16-diol was converted into (15R)-6α,11,12,16-tetrahydroxy-8,11,13-abietatrien-7-one (3a) and (15R)-6,11,12,16-tetrahydroxy-5,8,11,13-abietatetraen-7-one (4a), which were identical with natural products. For direct comparisons with 3a and 4a, (15S)-6α,11,12,16-tetrahydroxy-8,11,13-abietatrien-7-one (3b) and (15S)-6,11,12,16-tetrahydroxy-5,8,11,13-abietatetraen-7-one (4b) were also synthesized from (15S)-8,11,13-abietatriene-12,16-diol. The synthetic 3b and 4b were not identical with the natural products. From the present study, the absolute configurations of nellionol and 5-dehydronellionol were conclusively assigned as 5S,6R,10S,15R (3a) and 10R,15R (4a), respectively.

Complexation of 4‐dimethylaminoazobenzene with various kinds of cyclodextrins: Effects of cyclodextrins on the thermal cis‐to‐trans isomerization

“…1 can be analyzed according to the Benesi–Hildebrand (B‐H) equation (Eq. 2) 9: Here [T] 0 is the total concentration of DAAB, Δε is the difference in the molar extinction coefficients for bound and unbound DAAB, and Δ E is the change in the absorption intensity of DAAB solution on adding CD. As shown in Fig.…”

New Abietane Diterpenoids from the Mangrove Avicennia marina

“…Column chromatography, silica gel 60 M (Macherey-Nagel, 230 -400 mesh); Sephadex LH-20 (Pharmacia); TLC, silica gel plates (Macherey-Nagel, Sil G/UV 254 , 0.20 mm), spots were detected under UV light and after staining with anisaldehyde/H 2 SO 4 (1 %/5 %); Optical rotation was measured on a Propol Digital Automatic Polarimeter; IR spectra were recorded on Bruker IFS55 spectrometer; UV spectra were obtained on Varian 7, and diacetylmartynoside (8). Structure elucidation of the new compounds was accomplished by analysis of their spectroscopic data.…”

“…In a continuing search for new bioactive compounds from mangroves, we have investigated the chemical constituents of the twigs of A. marina collected from the coast of Xiamen in the mainland of China. In this paper, we describe the isolation and structural elucidation of three new abietane diterpenoids, 11-hydroxy-8,11,13abietatriene 12-O-β-xylopyranoside (1), a mixture of 6Hα-11,12,16-trihydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial 11,6-hemiacetal (2) and 6Hβ-11,12,16-trihydroxy-6,7-secoabieta-8,11,13triene-6,7-dial 11,6-hemiacetal (3), as well as the new lignan (7′S * ,8′R * )-4,4′,9′-trihydroxy-3,3′,5,5′tetramethoxy-7,8-dehydro-9-al-2,7′-cyclolignan (5), along with the known compounds 6,11,12,16tetrahydroxy-5,8,11,13-abitetetraen-7-one (4) [7], [8], lyoniresinol (6) [9], lyoniresinol 9′-O-β-D-glucopyranoside (7) [10], and diacetylmartynoside (8) [11] (• " Fig. 1).…”

“…The structures of compounds 1 -3 and 5 were determined on the basis of NMR spectroscopic analysis as well as UV, IR and mass spectra. As no 13 C-NMR and only incomplete 1 H-NMR assignments of 4 were reported before, we provide the complete set of NMR data of 4 in this paper [7], [8]. Results of biological testing are presented for these compounds regarding antiproliferative, cytotoxic and antimicrobial activities.…”

“…Compound 4 was identified as 6,11,12,16-tetrahydroxy-5,8,11,13abitetetraen-7-one by HR-MS and NMR data, which was firstly isolated from Premna latifolia in 1978 [19]. Full assignments of 1 H-and 13 C-NMR data were obtained by COSY, HMQC, HMBC, and NOESY spectra and are provided here due to incomplete literature data [7], [8], [19]. .…”