scholarly journals A New Diterpenoid with a Rearranged Skeleton from Salvia prattii

2017 ◽  
Vol 12 (8) ◽  
pp. 1934578X1701200
Author(s):  
Hiroshi Kawabe ◽  
Riyo Suzuki ◽  
Hiroshi Hirota ◽  
Keiichi Matsuzaki ◽  
Xun Gong ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Hela Cell ◽  
Cell Lines ◽  
Absolute Configuration ◽  
Electronic Circular Dichroism ◽  
Methyl Group ◽  
Spectroscopic Analyses ◽  
Hela Cell Lines ◽  
The Absolute ◽  
Circular Dichroïsm

A new diterpenoid with a rearranged skeleton, prattinin A (1), was isolated along with five known compounds (2–6) from the roots of Salvia prattii. The structure of 1 bearing a methyl group at the C-5 position was established by extensive spectroscopic analyses and the absolute configuration of 1 was elucidated by comparing the calculated and experimental electronic circular dichroism (ECD) spectra. Compounds 1, 3, 4, and 5 exhibited moderate or weak cytotoxicity against HL-60 and HeLa cell lines.

scholarly journals New Cytotoxic Cytochalasans from a Plant-Associated Fungus Chaetomium globosum kz-19

Marine Drugs ◽  
2021 ◽  
Vol 19 (8) ◽  
pp. 438
Author(s):  
Tantan Li ◽  
Yun Wang ◽  
Li Li ◽  
Mengyue Tang ◽  
Qinghong Meng ◽  
...  
Keyword(s):  
Hela Cell ◽  
Cell Lines ◽  
Absolute Configuration ◽  
2D Nmr ◽  
Chaetomium Globosum ◽  
Electronic Circular Dichroism ◽  
Spectroscopic Analyses ◽  
Hela Cell Lines ◽  
Ic50 Values ◽  
The Absolute

Four new cytochalasans, phychaetoglobins A–D (1–4), together with twelve known cytochalasans (5–16), were isolated from a mangrove-associated fungus Chaetomium globosum kz-19. The new structures were elucidated on the basis of extensive 1D and 2D NMR, HR ESIMS spectroscopic analyses, and electronic circular dichroism (ECD) calculations. The absolute configuration of 2 was established by application of Mosher’s method. Compounds 4–8 exhibited moderate cytotoxicities against A549 and HeLa cell lines with the IC50 values less than 20 μM.

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.

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 Use of Circular Dichroism to Determine the Absolute Configuration of a Pimarane Diterpenoid from the Southern African Sclerocroton integerrimus (Euphorbiaceae)

2014 ◽  
Vol 9 (8) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Vuyelwa J. Tembu ◽  
Moses K. Langat ◽  
Neil R. Crouch ◽  
Dulcie A. Mulholland
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Spectroscopic Analysis ◽  
Stem Bark ◽  
Electronic Circular Dichroism ◽  
The Absolute ◽  
Circular Dichroïsm

From the stem bark and leaves of Sclerocroton integerrimus, eight compounds, including 17-hydroxy- ent-pimara-8(14),15-dien-3-one (1), were isolated. The structures of the compounds were determined on the basis of spectroscopic analysis. The absolute configuration of 17-hydroxy- ent-pimara-8(14),15-dien-3-one was confirmed from electronic circular dichroism studies.

scholarly journals α-Photooxygenation of chiral aldehydes with singlet oxygen

2019 ◽  
Vol 15 ◽  
pp. 2076-2084 ◽  
Author(s):  
Dominika J Walaszek ◽  
Magdalena Jawiczuk ◽  
Jakub Durka ◽  
Olga Drapała ◽  
Dorota Gryko
Keyword(s):  
Circular Dichroism ◽  
Singlet Oxygen ◽  
Absolute Configuration ◽  
Dft Methods ◽  
Catalyst Structure ◽  
Electronic Circular Dichroism ◽  
Silyl Ethers ◽  
Td Dft ◽  
The Absolute ◽  
Circular Dichroïsm

Organocatalytic α-oxygenation of chiral aldehydes with photochemically generated singlet oxygen allows synthesizing chiral 3-substituted 1,2-diols. Stereochemical results indicate that the reaction in the presence of diarylprolinol silyl ethers is highly diastereoselective and that the configuration of a newly created stereocenter at the α-position depends predominantly on the catalyst structure. The absolute configuration of chiral 1,2-diols has been unambiguously established based on electronic circular dichroism (ECD) and TD-DFT methods.

scholarly journals Aspidoptoids A–D: Four New Diterpenoids from Aspidopterys obcordata Vine

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 529
Author(s):  
Sun ◽  
Cao ◽  
Xiao ◽  
Zhang ◽  
Wang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Circular Dichroism ◽  
Absolute Configuration ◽  
2D Nmr ◽  
Cytotoxic Activities ◽  
No Production ◽  
Inhibitory Effects ◽  
Electronic Circular Dichroism ◽  
Spectroscopic Analyses ◽  
Circular Dichroïsm

Four new diterpenoids, named aspidoptoids A–D (1–4), together with two known analogues (5–6) were isolated from Aspidopterys obcordata vine. Aspidoptoids A–B (1–2) are the first examples of phenylethylene-bearing 20-nor-diterpenoids of which aspidoptoid B (2) possesses a rare 3,10-oxybridge. Their structures and absolute configuration were determined by extensive spectroscopic analyses (IR, HRESIMS, 1D and 2D NMR) and electronic circular dichroism (ECD) calculation. In addition, all the isolates were evaluated for their cytotoxic activities and inhibitory effects on the nitric oxide (NO) production.

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