(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

1988 ◽  
Vol 53 (11) ◽  
pp. 2447-2472 ◽  
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.

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

RSC Advances ◽  
2016 ◽  
Vol 6 (85) ◽  
pp. 81461-81465 ◽  
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.

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

2015 ◽  
Vol 10 (6) ◽  
pp. 1934578X1501000 ◽  
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.

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

2017 ◽  
Vol 46 (13) ◽  
pp. 4397-4402 ◽  
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.

Crystal structure of aristoserratine

1983 ◽  
Vol 36 (5) ◽  
pp. 1037 ◽  
Author(s):  
IRC Bick ◽  
MA Hai ◽  
VA Patrick ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Circular Dichroism ◽  
Single Crystal ◽  
Absolute Configuration ◽  
Circular Dichroism Spectrum ◽  
X Ray Diffraction ◽  
Relative Configuration ◽  
X Ray ◽  
The Absolute ◽  
Circular Dichroïsm

The crystal structure of the alkaloid aristoserratine,* C20H24N2O, has been determined by single-crystal X-ray diffraction methods at 295 K, the structure being refined to a residual of 0.034 for 1107 independent 'observed' reflections. Crystals are monoclinic, P21, a 14.836(5), b 8.568(3), c 6.633(3) �, β 98.05(3)�, Z 2. The relative configuration is established and, by inference, by comparison of the circular dichroism spectrum with that of aristoteline, the absolute configuration is assigned.

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

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.

Absolute configuration of Tröger bases: an X-ray diffraction and circular dichroism study

2006 ◽  
Vol 47 (3) ◽  
pp. 319-321 ◽  
Author(s):  
Denis A. Lenev ◽  
Konstantin A. Lyssenko ◽  
Denis G. Golovanov ◽  
Oleg R. Malyshev ◽  
Pavel A. Levkin ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Circular Dichroïsm

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

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.

Vibrational Circular Dichroism (VCD), VCD Exciton Coupling, and X-ray Determination of the Absolute Configuration of an α ,β -Unsaturated Germacranolide

Chirality ◽  
2015 ◽  
Vol 27 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Mariano Sánchez-Castellanos ◽  
María A. Bucio ◽  
Angelina Hernández-Barragán ◽  
Pedro Joseph-Nathan ◽  
Gabriel Cuevas ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Vibrational Circular Dichroism ◽  
X Ray ◽  
Exciton Coupling ◽  
The Absolute ◽  
Circular Dichroïsm
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