Absolute configuration by vibrational circular dichroism of anti-inflammatory macrolide briarane diterpenoids from the Gorgonian Briareum asbestinum

AbstractThe four new briarane diterpenoids 2-butyryloxybriarane B-3 (2), 9-acetylbriarenolide S (3), briarenolide W (4), and 12-isobriarenolide P (5), along with briarane B-3 (1) and the five known diterpenes 6–10 were isolated from the gorgonian coral Briareum asbestinum collected from the Mexican Caribbean Sea. The structures were elucidated by 1D and 2D NMR and MS measurements. Since the structure of briarane B-3 (1) was only suggested and published without any spectroscopic support, it was herein confirmed, and the supporting data are now provided. In addition, 1 provided the opportunity to explore the sensitivity of vibrational circular dichroism (VCD) to determine the configuration of a single stereogenic center in the presence of eight other stereogenic centers in a molecule possessing a highly flexible ten-member ring. A single-crystal X-ray diffraction study, in which the Flack and Hooft parameters of 1 were determined, further confirmed that briarane B-3 is (1S,2S,6S,7R,8R,9S,10S,11R,17R)-1. This paper reports for first time the use of VCD in briarane diterpenes and with the presence of chlorine atoms. Biological evaluation of seven isolated compounds evidenced a moderate anti-inflammatory activity for compounds 6 and 9 but it did not show any cytotoxic, antiviral, antibacterial, and topoisomerase inhibitory activity.

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Absolute configuration of the antimalarial erythro-mefloquine – vibrational circular dichroism and X-ray diffraction studies of mefloquine and its thiourea derivative

RSC Advances ◽

10.1039/c6ra19367f ◽

2016 ◽

Vol 6 (85) ◽

pp. 81461-81465 ◽

Cited By ~ 4

Author(s):

M. Kohout ◽

J. Vandenbussche ◽

A. Roller ◽

J. Tůma ◽

J. Bogaerts ◽

...

Keyword(s):

Circular Dichroism ◽

Absolute Configuration ◽

Circular Dichroism Spectroscopy ◽

Vibrational Circular Dichroism ◽

X Ray Diffraction ◽

Thiourea Derivative ◽

X Ray ◽

The Absolute ◽

Circular Dichroïsm

The long-standing discussion of the absolute configuration of erythro-mefloquine is revisited, showcasing the strength of a combination of experimental and calculated vibrational circular dichroism spectroscopy.

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Absolute Configuration Assignment of 3′,4′-di-O-acylkhellactones Using Vibrational Circular Dichroism Exciton Chirality

Natural Product Communications ◽

10.1177/1934578x1501000658 ◽

2015 ◽

Vol 10 (6) ◽

pp. 1934578X1501000 ◽

Cited By ~ 3

Author(s):

Abigail I. Buendía-Trujillo ◽

J. Martín Torrres-Valencia ◽

Pedro Joseph-Nathan ◽

Eleuterio Burgueño-Tapia

Keyword(s):

Circular Dichroism ◽

Diffraction Analysis ◽

Absolute Configuration ◽

Optical Rotation ◽

Vibrational Circular Dichroism ◽

X Ray Diffraction ◽

X Ray ◽

Aerial Parts ◽

Configuration Assignment ◽

Circular Dichroïsm

The 3′R,4 ‘R absolute configuration (AC) of the angular-type pyranocoumarins (-)-3′,4′-di- O-acetylkhellactone (2), (-)-4′- O-acetyl-3′- O-angeloylkhellactone (3), (+)-3′- O-acetyl-4- O-isobutyroylkhellactone (4), and (-)-3′- O-angeloyl-4′- O-senecioylkhellactone (5), isolated from the aerial parts of Prionosciadum thapsoides, was assigned by vibrational circular dichroism exciton chirality (VCDEC), and confirmed by comparison of their VCD frequencies with those calculated using DFT at the B3LYP/DGDZVP level. This again reveals that AC assignments based on optical rotation data are not very confident. Evaluation of Flack and Hooft parameters obtained after single-crystal X-ray diffraction analysis of 3, independently confirmed this AC.

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(1S,7S)-7-Methyl-6,9-diazatricyclo[6,3,0,01,6]tridecane-5,10-dione, a tricyclic spirodilactam containing non-planar amide groups: Synthesis, NMR, crystal structure, absolute configuration, electronic and vibrational circular dichroism

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19882447 ◽

1988 ◽

Vol 53 (11) ◽

pp. 2447-2472 ◽

Cited By ~ 7

Author(s):

Petr Maloň ◽

C. L. Barness ◽

Miloš Buděšínský ◽

Rina K. Dukor ◽

Dick Van der Helm ◽

...

Keyword(s):

Crystal Structure ◽

Circular Dichroism ◽

Absolute Configuration ◽

Optically Active ◽

Vibrational Circular Dichroism ◽

X Ray Diffraction ◽

X Ray ◽

Circular Dichroïsm ◽

C Nmr ◽

Active Precursor

The title spirocyclic dilactam (1S,7S)-7-methyl-6,9-diazatricyclo[6,3,0,01,6]tridecan-5,10-dione (I), a molecule designed to contain non-planar amide groups, has been synthesized from an optically active precursor of known absolute configuration. The relative and absolute configuration have been determined by X-ray diffraction. The conformation of the compound has been investigated by X-ray, 1H and 13C NMR, electronic and vibrational circular dichroism. The compound possesses moderately non-planar amide groups in the two rings of nonequal geometry. The electronic CD is dominated by inherent chirality of the amide chromophores. The dilactams I and II ((1S,6S)-6-methyl-5,8-diazatricyclo[6,3,0,01,5]undecan-4,9-dione – having five-membered rings) exhibit monosignate amide I VCD and strong VCD bands in the mid-ir region.

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A Novel Azaphilone Muyophilone A From the Endophytic Fungus Muyocopron laterale 0307-2

Frontiers in Chemistry ◽

10.3389/fchem.2021.734822 ◽

2021 ◽

Vol 9 ◽

Author(s):

Chao Yuan ◽

Yuhua Guo ◽

Ke Wang ◽

Zhunian Wang ◽

Longfei Li ◽

...

Keyword(s):

Circular Dichroism ◽

Nmr Spectroscopy ◽

Single Crystal ◽

Endophytic Fungus ◽

Vibrational Circular Dichroism ◽

Spectroscopic Methods ◽

X Ray Diffraction ◽

X Ray ◽

Spectroscopic Analyses ◽

Circular Dichroïsm

Two known azaphilone derivatives, 4,6-dimethylcurvulinic acid (1) and austdiol (2), and their novel heterotrimer, muyophilone A (3), were isolated and identified from an endophytic fungus, Muyocopron laterale 0307-2. Their structures and stereochemistry were established by extensive spectroscopic analyses including HRMS, NMR spectroscopy, electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) spectroscopic methods, as well as single crystal X-ray diffraction. In the structure of 3, two compound 2-derived azaphilone units were connected through an unprecedented five-membered carbon bridge which was proposed to be originated from compound 1. Compound 3 represents the first example of azaphilone heterotrimers.

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Vibrational circular dichroism and single crystal X-Ray diffraction analyses of [Ir(bzq)2(phen)]+ (bzq = benzo[h]quinoline; phen = 1,10-phenanthroline): absolute configuration and role of CH–π interaction in molecular packing

Dalton Transactions ◽

10.1039/c7dt00606c ◽

2017 ◽

Vol 46 (13) ◽

pp. 4397-4402 ◽

Cited By ~ 11

Author(s):

Kazuyoshi Takimoto ◽

Yutaka Watanabe ◽

Shigeki Mori ◽

Hisako Sato

Keyword(s):

Circular Dichroism ◽

Single Crystal ◽

Absolute Configuration ◽

Molecular Packing ◽

Vibrational Circular Dichroism ◽

X Ray Diffraction ◽

X Ray ◽

The Absolute ◽

Circular Dichroïsm

The absolute configuration of a cationic iridium(iii) complex was determined in solution and solid by vibrational circular dichroism and X-ray diffraction analyses.

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Vibrational Circular Dichroism Absolute Configuration of 9,12-Cyclomulin-13-ol, a Diterpene from Azorella and Laretia Species

Natural Product Communications ◽

10.1177/1934578x1501000805 ◽

2015 ◽

Vol 10 (8) ◽

pp. 1934578X1501000

Author(s):

Marcelo A. Muñoz ◽

Aurelio San-Martín ◽

Pedro Joseph-Nathan

Keyword(s):

Density Functional Theory ◽

Circular Dichroism ◽

Absolute Configuration ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Vibrational Circular Dichroism ◽

X Ray Diffraction ◽

Functional Theory ◽

X Ray ◽

Circular Dichroïsm

The absolute configuration of the diterpenoid 9,12-cyclomulin-13-ol (1), a constituent of Azorella and Laretia species, has been established by vibrational circular dichroism spectroscopy in combination with density functional theory calculations. The obtained normal diterpene absolute configuration confirms that of azorellanol (2), which was determined by single crystal X-ray diffraction.

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