scholarly journals A Phenylpropanoid and Biflavonoids from the Needles of Cephalotaxus harringtonia var. harringtonia

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201 ◽  
Author(s):  
Anju Mendiratta (Nee Chugh) ◽  
Rameshwar Dayal ◽  
John P. Bartley ◽  
Graham Smith
Keyword(s):  
Nmr Spectroscopy ◽  
Oral Dose ◽  
Spectral Data ◽  
2D Nmr ◽  
Hepatoprotective Activity ◽  
X Ray Diffraction ◽  
Soluble Extract ◽  
2D Nmr Spectroscopy ◽  
X Ray ◽  
First Time

A phenylpropanoid [2-(3-methoxy-4-hydroxyphenyl)-propane-1,3-diol] (1) together with four known biflavonoids namely 7, 4′, 7′″, 4′″-tetra- O-methyl amentoflavone (2); 7, 4′, 7″-tri- O-methyl amentoflavone (3); ginkgetin (4); sequoiaflavone (5) were isolated from the acetone soluble extract of needles of Cephalotaxus harringtonia var. harringtonia. Their structures were elucidated mainly on the basis of interpretation of 1D and 2D NMR spectroscopy and X-ray diffraction studies. The detailed spectral data of phenylpropanoid have been described for the first time. Ginkgetin (4) exhibited significant hepatoprotective activity in rat at 6 mg/kg oral dose level.

scholarly journals Guaiane Sesquiterpenoids from Jatropha curcas

2008 ◽  
Vol 3 (10) ◽  
pp. 1934578X0800301
Author(s):  
Xia-Chang Wang ◽  
Shi-Ping Ma ◽  
Jing-Han Liu ◽  
Li-Hong Hu
Keyword(s):  
Nmr Spectroscopy ◽  
Spectral Data ◽  
Jatropha Curcas ◽  
2D Nmr ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
2D Nmr Spectroscopy ◽  
X Ray ◽  
Esi Ms ◽  
Related Compounds

Two new guaiane sesquiterpenoids named jatrophaols A and B (1, 2), along with three known analogues, were isolated from the roots of Jatropha curcas. Their structures were determined by spectroscopic methods, including 1D and 2D NMR spectroscopy, HR-EI-MS, HR-ESI-MS, and X-ray diffraction, as well as by comparison of their spectral data with those of related compounds.

(-)-Armepavine: Gradient-Enhanced 2D NMR Study and X-Ray Crystal Structure Determination

1997 ◽  
Vol 62 (10) ◽  
pp. 1623-1630 ◽  
Author(s):  
Radek Marek ◽  
Jaromír Marek ◽  
Jiří Dostál ◽  
Jiří Slavík
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Structure Determination ◽  
Nmr Assignment ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
2D Nmr Spectroscopy ◽  
X Ray ◽  
Nmr Study ◽  
Benzylisoquinoline Alkaloid

(-)-Armepavine, a benzylisoquinoline alkaloid isolated from Papaver caucasicum, was examined by gradient-enhanced 2D NMR spectroscopy and X-ray diffraction analysis. Unambiguous 1H, 13C, and 15N NMR assignment of the title alkaloid is reported.

scholarly journals Absolute Configuration of Cembrane Diterpenoids from Bursera multijuga

2014 ◽  
Vol 9 (9) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Juan D. Hernández-Hernández ◽  
Hugo A. García-Gutiérrez ◽  
Luisa U. Román-Marín ◽  
Yunuen I. Torres-Blanco ◽  
Carlos M. Cerda-García-Rojas ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Absolute Configuration ◽  
2D Nmr ◽  
Vibrational Circular Dichroism ◽  
Conformational Preference ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Absolute ◽  
First Time ◽  
Good Agreement

The stems of Bursera multijuga afforded (-)-(1 S,3 E,7 R,8 R,11 E)-7,8-epoxycembra-3,11-dien-1-ol (1) and its acetate 2, together with cembrene A (3), nephthenol (4), and cembrenol (5). The structures of 1 and 2 were elucidated by 1D and 2D NMR, HRESIMS, and X-ray diffraction. The conformational preference of flexible 1 was studied by molecular modeling at the DFT B3LYP/DGDZVP level of theory. Good agreement between calculated and experimental vibrational circular dichroism curves established the absolute configuration of 1. This is the first time that cembrane derivatives have been isolated from the genus Bursera.

scholarly journals Two Dibenzoquinones from the Fungus Acremonium cavaraeanum

2017 ◽  
Vol 12 (11) ◽  
pp. 1934578X1701201
Author(s):  
Qiao Xu ◽  
Miao-Miao Zhang ◽  
Shu-Zhen Yana ◽  
Lu-Fen Cao ◽  
Qiang Lia ◽  
...  
Keyword(s):  
Single Crystal ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time

Two symmetrical dibenzoquinone derivatives were isolated from solid cultures of the fungus Acremonium cavaraeanum. Compound 1 was new and identified as 2,7-dihydroxy-3,6,9-trimethyl-9 H-xanthene-1,4,5,8-tetraone. Compound 2 was 3,3’,6,6’-tetrahydroxy-4,4’-dimethyl-1,1’-bi- p-benzoquinone, i.e. oosporein, which was reported from A. cavaraeanum for the first time. The structure of the dibenzoquinone (1) was unambiguously elucidated using a combination of MS, IR, 1D- and 2D-NMR, and the dibenzoquinone (2) was further determined by single-crystal X-ray diffraction.

scholarly journals Two New Isomers of Palmityl-4-hydroxycinnamate from Flowers of Taraxacum Species

2016 ◽  
Vol 11 (6) ◽  
pp. 1934578X1601100
Author(s):  
Matej Dudáš ◽  
Mária Vilková ◽  
Tibor Béres ◽  
Miroslav Repčák ◽  
Pavol Mártonfi
Keyword(s):  
Nmr Spectroscopy ◽  
Pollen Grains ◽  
2D Nmr ◽  
Male Sterile ◽  
2D Nmr Spectroscopy ◽  
First Time

Two isomers, (Z)- and (E)-palmityl 4-hydroxycinnamate [hexadecyl(2Z)-3-(4-hydroxyphenyl)prop-2-enoate and hexadecyl(2E)-3-(4-hydroxyphenyl)prop-2-enoate] were isolated for the first time from ligulate flowers of Taraxacum linearisquameum Soest (sect. Taraxacum). The highest amount of these compounds was detected in pollen grains; 0.26 mg/100 mg DW of the (E)-isomer and 0.096 mg/100 mg DW of the (Z)-isomer. The structures of these compounds were elucidated by a combination of HPLC-ESI-Qtof-MS and ID and 2D NMR spectroscopy. Their presence was confirmed in other species of Taraxacum, but they were not found in the male-sterile triploid agamospermous taxon T. parnassicum.

scholarly journals Two New 8, 14-seco-pregnane Steroidal Aglycones from Roots of Cynanchum bungei

2016 ◽  
Vol 11 (12) ◽  
pp. 1934578X1601101
Author(s):  
Jia-Wen Zhao ◽  
Feng-Yang Chen ◽  
Li-Juan Gao ◽  
Shi-Fang Xu ◽  
Shu-Juan Hao ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
2D Nmr ◽  
Spectroscopic Methods ◽  
Soluble Extract ◽  
2D Nmr Spectroscopy ◽  
Chemical Evidence

Two new 8, 14-seco skeleton C21 steroidal aglycones, cynanbungeigenin A ( 1 ) and cynanbungeigenin B ( 2 ), were isolated from the hydrolyzed extract of the EtOAc soluble extract of the roots of Cynanchum bungei. Their structures were determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D and 2D NMR spectroscopy.

Structural Studies of Chelirubine and Chelilutine Free Bases

1998 ◽  
Vol 63 (7) ◽  
pp. 1045-1055 ◽  
Author(s):  
Jiří Dostál ◽  
Jiří Slavík ◽  
Milan Potáček ◽  
Radek Marek ◽  
Otakar Humpa ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Quantum Chemical ◽  
2D Nmr ◽  
Molecular Symmetry ◽  
Structural Studies ◽  
Free Base ◽  
2D Nmr Spectroscopy ◽  
Sanguinaria Canadensis ◽  
First Time

The structures of chelirubine and chelilutine free bases have been examined by 2D NMR spectroscopy and mass spectrometry. Chelirubine chloride (1a) upon treatment with Na2CO3 yielded free base which possessed the constitution of bis(5,6-dihydrochelirubin-6-yl) ether (2a). The free base of chelilutine (1b) was determined to be bis(5,6-dihydrochelilutin-6-yl) ether (2b). The aqueous NH3 treatment of chelilutine (1b) produced bis(5,6-dihydrochelilutin-6-yl)amine (3b). 6-Hydroxy-5,6-dihydrochelirubine (4a) and 6-hydroxy-5,6-dihydrochelilutine (4b) were detected only in CDCl3 solution by NMR spectroscopy. In CDCl3, the compound 2b underwent hydrolysis to 4b that was immediately followed by the reverse condensation to a diastereomer of 2b. Pseudokinetics of this reaction was followed by NMR spectroscopy and quantum chemical calculations were carried out to support the suggested type of molecular symmetry alteration. The known alkaloid dihydrochelirubine (5) was isolated for the first time from Sanguinaria canadensis.

scholarly journals Synthesis and characterization of allyl- and vinyl-substituted 1,2-bis(tetrazolo)ethanes as polymeric precursors

2016 ◽  
Vol 71 (12) ◽  
pp. 1199-1209
Author(s):  
Vera A. Hartdegen ◽  
Maximilian S. Hofmayer ◽  
Konstantin Karaghiosoff ◽  
Thomas M. Klapötke
Keyword(s):  
Allyl Bromide ◽  
2D Nmr ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
2D Nmr Spectroscopy ◽  
X Ray ◽  
Physical Stimuli ◽  
Thermal Stability Of

AbstractOn the basis of 1,2-bis(5-tetrazolo)ethane (BTE) the corresponding twofold vinyl and allyl N-substituted derivatives were synthesized using 1,2-dibromoethane and allyl bromide, respectively. The compounds were obtained as two different constitutional isomers. Both species were analyzed using NMR and IR spectroscopy, elemental analysis, as well as mass spectrometry. In the case of the diallyl bistetrazoles, the two isomers were characterized using 2D NMR spectroscopy. The synthesis of the divinyl compounds gave crystals of the 2,2′-N-substituted isomer, which were analyzed by single-crystal X-ray diffraction. The thermal stability of the compounds was determined using differential scanning calorimetry (DSC) and gave decomposition temperatures around 190°C and 230°C. For the investigation of the inherent energetic potential, sensitivities toward physical stimuli and detonation parameters were determined. The compounds turned out to be insensitive toward friction and impact and possess moderate energetic properties.

Synthesis of the 4-Pyridine Analog of Kostanecki's Triketone. Determination of Constitution and Stereochemistry by 2D-NMR Spectroscopy and X-ray Structural Analysis

1991 ◽  
Vol 1991 (12) ◽  
pp. 1337-1341 ◽  
Author(s):  
Horst Kessler ◽  
Siggi Mronga ◽  
Bernhard Kutscher ◽  
Arndt Müller ◽  
William S. Sheldrick
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
2D Nmr ◽  
2D Nmr Spectroscopy ◽  
X Ray

Chiral Polymorphic Hydrazine-based Asymmetric Liquid Crystal Trimers with Resorcinol as Linking Group

2021 ◽  
Vol 18 ◽  
Author(s):  
Wan-Sinn Yam ◽  
Yit-Peng Goh ◽  
Foo-Win Yip ◽  
Gurumurthy Hegde
Keyword(s):  
Liquid Crystal ◽  
2D Nmr ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
2D Nmr Spectroscopy ◽  
Spacer Length ◽  
X Ray ◽  
Phase Sequence ◽  
Molecular Length ◽  
Ft Ir

Introduction: This is the first report on chiral polymorphic hydrazine-based asymmetric liquid crystal trimers, 1-[4'-(4''- (5-Cholesteryloxy)carbonyl)butyloxy]-3-[N-benzylideneoxy-N'-(4'''-decyloxybenzylidene)hydrazine] butyloxybenzenes, and 1-[4'-(4''-(10-cholesteryloxy)carbonyl)nonyloxy]-3-[N-benzylideneoxy-N'-(4'''- decyloxybenzylidene)hydrazine]butyloxybenzenes., in which the hydrazine and cholesterol arms were connected via two flexible methylene spacers (n = 3-12 units and m = 4 or 9, respectively) to the central resorcinol core. Materials and Methods: FT-IR, 1D and 2D NMR spectroscopy, and CHN microanalysis were used to elucidate the structures of the trimers. Differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction were used to study the transitional and phase properties of the trimers, of which they were length and spacer parity dependent. Trimers with short spacer length in the cholesteryl arm, m = 4 showed interesting phase sequence of BP/N*-TGBA*-SmA*. Results and discussion: The TGBA∗ phase was sensitive to spacer length as it was only observed in trimers with short ester linkage. For the long analogues, m = 9, characteristic visible reflection and a much simpler phase sequence with only N* and SmA* phases were seen. Conclusion: The X-ray diffraction measurements revealed that layer periodicities of the SmA* phase were approximately half the estimated all-trans molecular length (d/L ≈ 0.44-0.52), thus suggesting that the molecules are either strongly intercalated or bent.

Sign in / Sign up

Export Citation Format

Share Document