MWL fraction with a high concentration of lignin-carbohydrate linkages: Isolation and 2D NMR spectroscopic analysis

Holzforschung ◽  
2007 ◽  
Vol 61 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mikhail Yu. Balakshin ◽  
Ewellyn A. Capanema ◽  
Hou-min Chang

Abstract A preparation enriched in lignin-carbohydrate fragments (LCC-AcOH) was isolated in the course of purification of loblolly pine crude milled wood lignin (MWL). The preparation contained approximately equal amounts of lignin and carbohydrates, with high amounts of arabinose and galactose compared to their levels in wood. LCC-AcOH was investigated by 2D 1H-13C (HMQC and HMBC) correlation NMR techniques and quantitative 13C NMR. The HMQC spectra allowed direct detection of phenyl glycoside, ester and benzyl ether lignin-carbohydrates linkages in high amounts. The assignment of these structures was supported by the HMBC technique. It is noteworthy that in the ester lignin-carbohydrate linkages, a uronic acid residue was attached not to the benzylic position of lignin, as commonly believed, but to the γ-position of the side chain.

1995 ◽  
Vol 60 (4) ◽  
pp. 619-635 ◽  
Author(s):  
Václav Křeček ◽  
Stanislav Hilgard ◽  
Miloš Buděšínský ◽  
Alois Vystrčil

A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1H NMR, 13C NMR and IR spectroscopy. The kind of intramolecular association of the 17α-hydroxy group was studied in connection with modification of the side chain and substitution in position 22a. Complete assignment of the hydrogen signals and most of the coupling constants was accomplished using a combination of 1D and 2D NMR techniques. The 1H and 13C NMR spectra are discussed.


2007 ◽  
Vol 62 (4) ◽  
pp. 569-572 ◽  
Author(s):  
Jun Wu ◽  
Haixin Ding ◽  
Minyi Li ◽  
Si Zhang

Xylogranatin E, the second phragmalin with a rare oxygen bridge between C1 and C29 found in nature, was isolated from the fruit of a Chinese mangrove, Xylocarpus granatum. Its structure was determined by spectroscopic analysis. Complete assignment of 1H and 13C NMR data of xylogranatin E was achieved by 2D NMR techniques, including 1H-1H COSY, HSQC, HMBC and NOESY spectra.


2019 ◽  
Vol 16 (6) ◽  
pp. 474-477 ◽  
Author(s):  
Pham Van Khang ◽  
Nguyen Thi Hien Lan ◽  
Le Quang Truong ◽  
Mai Thi Minh Chau ◽  
Mai Xuan Truong ◽  
...  

In this report, two new steroidal glycosides were isolated and determined from n-butanol fraction of A.asphodeloides. The structures were confirmed in comparison with the spectral data of known compounds by using different spectroscopic analysis approaches including 1D & 2D-NMR techniques and HRMS. The anti-proliferation screening against cancer cell lines A549 and HeLa indicated that compound 1 exhibited good inhibitory activities with IC50 values of 0.79 and 0.55 µg/mL, respectively.


2001 ◽  
Vol 56 (7-8) ◽  
pp. 521-525 ◽  
Author(s):  
Denata Kasaj ◽  
Liselotte Krenn ◽  
Sonja Prinz ◽  
Antje Hüfner ◽  
Shi Shan Yuc ◽  
...  

The detailed investigation of a methanolic extract of aerial parts of Achillea pannonica SCHEELE. within a chemotaxonomic study led to the isolation of 6 flavonoid glycosides. Besides rutin, apigenin-7-O-glucopyranoside, luteolin-7-O-glucopyranoside, apigenin-7-O-rutinoside and acacetin-7-O-rutinoside, an unusual flavondiglucoside was isolated. Its structure was established by UV, 1HNMR and 13C NMR spectroscopic methods including 2D-NMR techniques and ESI-MS as luteolin-7,4′-O-β-diglucoside. This substance is reported for the first time in the genus Achillea. Chemotaxonomic aspects are discussed briefly


2015 ◽  
Vol 10 (12) ◽  
pp. 1934578X1501001 ◽  
Author(s):  
Zhi-Bo Chu ◽  
Jun Chang ◽  
Ying Zhu ◽  
Xun Sun

One new bifuran derivative (1), together with fourteen known compounds, were isolated from Cordyceps cicadae X. Q. Shing. The known compounds included nine nucleosides, uracil (2), uridine (3), 2′-deoxyuridine (4), 2′-deoxyinosine (5), guanosine (6), 2′-deoxyguanosine (7), thymidine (8), adenosine (9), and 2′-deoxyadenosine (10); three amino acids tryptophan (11), phenylalanine (12), and tyrosine (13); and two dopamine analogues N-acetylnoradrenaline (14) and its dimer, trans–2-(3′,4′-dihydroxyphenyl)-3-acetylamino-7-( N-acetyl-2″-amino-ethylene)-1,4-benzodioxane (15). Their structures were decisively elucidated by spectroscopic analysis, including 1D and 2D NMR techniques.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Bing-You Yang ◽  
Yong-Gang Xia ◽  
Yan-Yan Wang ◽  
Qiu-Hong Wang ◽  
Hai-Xue Kuang

Chemical investigation of 50% ethanol eluate fraction of macroporous resin for the flower of Datura metel L. collected in Jiangsu province of China resulted in the isolation of two novel naturally occurring norwithasteroids, baimantuoluoline I (1) and baimantuoluoside J (2). Their structures were elucidated as 5α, 6β, 12β-trihydroxy-1-oxo-2-en-ergosta-21,24;22,29-diepoxy-26-carboxylic acid (1) and 5α, 6β, 12β, 25-tetrahydroxy-1-oxo-2-en-ergosta-21,24;22,29-diepoxy-26-carboxylic acid (2) on the basis of extensive spectroscopic analysis, including 1D, 2D-NMR, and HR-ESI-MS. According to the literatures, this study represents the first report of the norwithasteroids in the side chain with unusual six- and seven-membered ether rings instead of those with an unmodified skeleton (δ-lactone or δ-lactol side chain) and a modified skeleton (γ-lactone or γ-lactol side chain) in the family of withanolides. Meanwhile, compounds 1 and 2 were evaluated for their immunosuppressive activity against mice splenocyte proliferation in vitro.


2013 ◽  
Vol 8 (4) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Gaimei She ◽  
Ruiyang Cheng ◽  
Lei Sha ◽  
Yixia Xu ◽  
Renbin Shi ◽  
...  

A new compound, mucic acid 3- O-gallate (1), was isolated from the fruit of Phyllanthus emblica L, together with 5 known compounds (2-6). Their structures were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR techniques, and by comparison with literature data.


2007 ◽  
Vol 62 (6) ◽  
pp. 859-862 ◽  
Author(s):  
Jun Wu ◽  
Minyi Li ◽  
Si Zhang ◽  
Qiang Xiao ◽  
Qingxin Li

A new mexicanolide and a new phragmalin, named 30α-hydroxyl xylogranatin A and xylogranatin E2, respectively, have been isolated from the seeds of a Chinese mangrove Xylocarpus granatum. Their structures were identified on the basis of spectroscopic data. Each of them has a 3-O-β -tigloyl group. The first complete assignments of 1H and 13C NMR data for these limonoids were achieved by means of 2D NMR techniques, including 1H-1H COSY, HSQC, HMBC and NOESY spectra


2012 ◽  
Vol 67 (5) ◽  
pp. 421-425 ◽  
Author(s):  
Umar Farooq ◽  
Afsar Khan ◽  
Saleha Suleman Khan ◽  
Shazia Iqbal ◽  
Rizwana Sarwar ◽  
...  

Phytochemical investigation of the whole plant of Achillea millefolium led to the isolation of three new sesquiterpenes which were trivially named as sesquiterpene lactone-esters A and B (1 and 2), and sesquiterpene lactone-diol (3). The structures of these compounds were determined with the help of one- and two-dimensional (1D and 2D) NMR techniques including 1H NMR, 13C NMR, HMQC, HMBC, COSY, and NOESY experiments.


1978 ◽  
Vol 33 (1-2) ◽  
pp. 149-150 ◽  
Author(s):  
J. B. Stothers ◽  
A. Stoessl ◽  
E. W. B. Ward

Abstract The mechanism of the biological hydroxylation of the isopropenyl side-chain of the sesquiterpene capsidiol, to give 13-hydroxycapsidiol, has been investigated with 13C-NMR techniques, using capsidiol biogenetically enriched with 13C from [1,2-13C2] acetate. The results indicate that neither an allylic rearrangement nor the formation of an epoxide intervene in the process.


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