scholarly journals Isolation and Absolute Configurations of Diversiform C17, C21 and C25 Terpenoids from the Marine Sponge Cacospongia sp.

Marine Drugs ◽  
2018 ◽  
Vol 17 (1) ◽  
pp. 14 ◽  
Author(s):  
Xingwang Zhang ◽  
Ping-Lin Li ◽  
Guo-Fei Qin ◽  
Shengying Li ◽  
Nicole de Voogd ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Cell Lines ◽  
Optical Rotation ◽  
Human Tumor ◽  
Chiral Hplc ◽  
Pure Compounds ◽  
New Compounds ◽  
First Time ◽  
Optically Pure ◽  
Circular Dichroïsm

Chemical investigation of MeOH extract of a South China Sea sponge Cacospongia sp. yielded 15 terpenoids belonging to three different skeleton-types, including the unusual C17 γ-lactone norditerpenoids (1–3), the rare C21 pyridine meroterpenoid (7), and the notable C25 manoalide-type sesterterpenoids (4–6, 8–10). Compounds 1–5 were initially obtained as enantiomers, and were further separated to be optically pure compounds (1a, 1b, 2a, 2b, 3a-r, 3b-r, 4a, 4b, 5a and 5b) by chiral HPLC, with a LiAlH4 reduction aid for 3. Compounds 3a/3b (a pair of inseparable enantiomers), 4a, 5a, 6, and 7 were identified as new compounds, while 1a/1b and 2a/2b were obtained from a natural source and were determined for their absolute configurations for the first time. This is also the first time to encounter enantiomers of the well-known manoalide-type sesterterpenoids from nature. The structures with absolute configurations of the new compounds were unambiguously determined by comprehensive methods including HR-ESI-MS and NMR data analysis, optical rotation comparison, experimental and calculated electronic circular dichroism (ECD), and Mo2(OAc)4 induced circular dichroism (ICD) methods. The cytotoxicity of the isolates against selected human tumor cell lines was evaluated, however, the tested compounds showed no activity against selected cell lines.

scholarly journals Trimeric and Dimeric Carbazole Alkaloids from Murraya microphylla

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5689
Author(s):  
Xiaoli Ma ◽  
Hongwei Chen ◽  
Sisi Zhu ◽  
Pengfei Tu ◽  
Yong Jiang
Keyword(s):  
Circular Dichroism ◽  
Data Analysis ◽  
Chiral Hplc ◽  
Hplc Separation ◽  
Electronic Circular Dichroism ◽  
Nmr Data ◽  
New Compounds ◽  
Optically Pure ◽  
Circular Dichroïsm ◽  
Carbazole Alkaloids

Seventeen new carbazole alkaloid derivatives, including a trimeric carbazole racemate, (±)-microphyltrine A (1), 15 dimeric carbazole racemates, (±)-microphyldines A–O (2–16), and a C-6–C-3″-methyl-linked dimeric carbazole, microphyldine P (17), were isolated from the leaves and stems of Murraya microphylla (Merr. et Chun) Swingle. The structures of the new compounds were elucidated on the basis of HRESIMS and NMR data analysis. The optically pure isomers of these isolated carbazole alkaloids were obtained by chiral HPLC separation and their absolute configurations were determined by electronic circular dichroism (ECD) data analysis.

Two Rare Hydroazulene-type Sesquiterpenes from the Roots of Aristolochia yunnanensis

2014 ◽  
Vol 69 (6) ◽  
pp. 742-746 ◽  
Author(s):  
Zhuo Du ◽  
Feng-Ni Wen ◽  
Ji-Ping Zhang ◽  
Jian-Feng Wua ◽  
Fang Liu ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Cell Lines ◽  
Spectroscopic Data ◽  
Cytotoxic Activities ◽  
Moderate Activity ◽  
Electronic Circular Dichroism ◽  
The Third ◽  
The Absolute ◽  
First Time ◽  
Circular Dichroïsm

Two new sesquiterpenes, named aristoyunnolin I (1) and J (2), together with eight known compounds (3 - 10) were isolated from the roots of Aristolochia yunnanensis. Compounds 1 and 2 feature a rare hydroazulene-type sesquiterpene skeleton and represent the third and fourth examples of this kind found in nature. The structures were determined from spectroscopic data, and the absolute configurations of 1 - 3 were assigned by comparing experimental with simulated electronic circular dichroism (ECD) spectra. Compounds 1, 2, 6 - 10 were isolated from this plant for the first time. The cytotoxic activities of 1 - 10 were evaluated against P-388 and A-549 cell lines. Only compounds 4 and 5 showed moderate activity with IC50 values ranging from 12.0 to 18.2 μM.

scholarly journals Chiroptical Studies of Flavanone

2013 ◽  
Vol 8 (8) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Marcelo A. Muñoz ◽  
María A. Bucio ◽  
Pedro Joseph-Nathan
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Vibrational Circular Dichroism ◽  
Chiral Hplc ◽  
Stereochemical Assignment ◽  
Td Dft ◽  
On Line ◽  
Circular Dichroïsm

Chiral HPLC coupled to electronic circular dichroism and laser optical rotation detection (HPLC-ECD-OR) permitted the on-line chiroptical characterization of both enantiomers of racemic flavanone (1) as ECD(-)310-OR(-)670-flavanone and ECD(+)310-OR(+)670-flavanone for the first and second eluted peaks, respectively. Calculation of the ECD spectrum of one enantiomer at the TD-DFT/DGTZVP level of theory yielded the ( S)-ECD(-)310-OR(-)670 and ( R)-ECD(+)310-OR(+)670-1 absolute configuration, in agreement with the use of empirical rules for stereochemical assignment. Vibrational circular dichroism spectra of enantiopure compounds, obtained through fraction collection during repeated HPLC runs, were recorded and compared with theoretical traces produced from DFT calculations at the B3LYP/DGDZVP and B3PW91/DGDZVP levels of theory, which further confirmed the absolute configuration obtained from the on-line chiroptical data.

scholarly journals Absolute Configuration Sensing of Chiral Aryl- and Aryloxy-Propionic Acids by Biphenyl Chiroptical Probes

Chemosensors ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 154
Author(s):  
Stefania Vergura ◽  
Stefano Orlando ◽  
Patrizia Scafato ◽  
Sandra Belviso ◽  
Stefano Superchi
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Optical Rotation ◽  
Environmental Pollutants ◽  
Red Shift ◽  
Electronic Circular Dichroism ◽  
Configuration Assignment ◽  
Clear Sign ◽  
The Absolute ◽  
Circular Dichroïsm

The absolute configuration of chiral 2-aryl and 2-aryloxy propionic acids, which are among the most common chiral environmental pollutants, has been readily and reliably established by either electronic circular dichroism spectroscopy or optical rotation measurements employing suitably designed 4,4′-disubstituted biphenyl probes. In fact, the 4,4′-biphenyl substitution gives rise to a red shift of the diagnostic electronic circular dichroism signal of the biphenyl A band employed for the configuration assignment, removing its overlap with other interfering dichroic bands and allowing its clear sign identification. The largest A band red shift, and thus the most reliable results, are obtained by employing as a probe the 4,4′-dinitro substituted biphenylazepine 3c. The method was applied to the absolute configuration assignment of 2-arylpropionic acids ibuprofen (1a), naproxen (1b), ketoprofen (1c) and flurbiprofen (1d), as well as to the 2-aryloxypropionic acids 2-phenoxypropionic acid (2a) and 2-naphthoxypropionic acid (2b). This approach, allowing us to reveal the sample’s absolute configuration by simple optical rotation measurements, is potentially applicable to online analyses of both the enantiomeric composition and absolute configuration of these chiral pollutants.

scholarly journals Labdane and Abietane Diterpenoids from Juniperus oblonga and Their Cytotoxic Activity

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1561 ◽  
Author(s):  
Qiao ◽  
Khutsishvili ◽  
Alizade ◽  
Atha ◽  
Borris
Keyword(s):  
Cell Lines ◽  
Human Tumor ◽  
2D Nmr ◽  
Human Tumor Cell Lines ◽  
Abietane Diterpenoids ◽  
Whole Plant ◽  
Phytochemical Investigation ◽  
Ic50 Values ◽  
First Time ◽  
Mcf 7

A phytochemical investigation of the whole plant of Juniperus oblonga led to the isolationof one previously undescribed labdane diterpenoid, (4R,5S,9S,10R)‐13‐des‐ethyl‐13‐oxolabda‐8(17),11E‐dien‐19‐oic acid (1), together with nine known diterpenoids (2–3, 6–12), two lignans (4, 5),and a coumarin (13). The structures of all the compounds were elucidated on the basis ofspectrometric data, primarily one‐dimensional (1D)‐ and two‐dimensional (2D)‐NMR and massspectrometry. Electronic circular dichroism (ECD) calculations determined the absoluteconfiguration of 1. In addition, the isolated compounds were evaluated for their cytotoxic activityagainst three human tumor cell lines (HepG2, MCF‐7, and HeLa). 6,12‐Dihydroxyabieta‐5,8,11,13‐tetraen‐7‐one (6) showed moderate cytotoxicity against all three cell lines with IC50 values rangingfrom 24.41 μM to 58.39 μM and trilobinone (10) showed weaker activity with IC50 values rangingfrom 56.93 μM to 79.98 μM. None of the isolated diterpenoids have been previously reported fromJuniperus oblonga, and five compounds are here reported from the genus Juniperus for the first time.

Chiral carbazole-based porphyrins showing absorption and circular dichroism in the near-infrared region

2020 ◽  
Vol 24 (01n03) ◽  
pp. 247-251
Author(s):  
Chihiro Maeda ◽  
Tadashi Ema
Keyword(s):  
Circular Dichroism ◽  
Near Infrared ◽  
Infrared Region ◽  
Nir Absorption ◽  
Near Infrared Region ◽  
Induced Aggregation ◽  
First Time ◽  
Circular Dichroïsm

Chiral carbazole-based porphyrins were synthesized for the first time via the incorporation of hydrobenzoin units at the thiophene moieties. They showed absorption and circular dichroism in the near-infrared (NIR) region. The NIR absorption was further red-shifted by solvent-induced aggregation.

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