Synthesis and characterization of Δ-cis(N)-trans(O5)-RR sodium bis-((S)-α-alaninato-N-monopropionato)cobaltate(III) isomer

1986 ◽  
Vol 51 (10) ◽  
pp. 2109-2115
Author(s):  
Bohumil Hájek ◽  
Jana Ondráčková ◽  
František Jursík
Keyword(s):  
Absolute Configuration ◽  
Synthesis And Characterization ◽  
Mutual Position ◽  
Molecular Models ◽  
Visible Absorption ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
C Nmr

Of the 12 possible diastereoisomers only Δ-cis(N)-trans(O5)-(RR)-Na[Co(alamp)2] isomer was isolated. Possible reasons explaining stereospecific coordination of ligand are discussed in terms of steric intra- and interligand interactions arising from the mutual position of -CH3 and N-CH2-CH2- groups. These exclude all isomers with SS or RS configuration of secondary nitrogen atoms. For the determination of the absolute configuration visible absorption, 1H, 13C NMR, circular dichroism and molecular models were employed.

(-)-Strempeliopine, stereoselective total synthesis and the determination of absolute configuration

1986 ◽  
Vol 51 (8) ◽  
pp. 1731-1742 ◽  
Author(s):  
Josef Hájíček ◽  
Jan Trojánek
Keyword(s):  
Circular Dichroism ◽  
Total Synthesis ◽  
Absolute Configuration ◽  
Determination Of Absolute Configuration ◽  
Natural Base ◽  
The Absolute ◽  
Circular Dichroïsm

A synthesis of (±)-strempeliopine (II) is described, the key step of which is the stereoselective reductive rearrangement of 18-methylene-1,2-dehydroaspidospermidine (XI). The absolute configuration of the natural (-)-base II was determined as (2S, 7R, 20R, 21R) on the basis of its synthesis from (+)-18-methylenevincadifformine (XVII) the configuration of which was derived from a comparison of circular dichroism properties of bases with a β-anilinoacrylate chromophore. The biogenesis of the alkaloids of the schizozygane type is discussed.

Absolute configuration determination of theanti-head-to-head photocyclodimer of anthracene-2-carboxylic acid through cocrystallization withL-prolinol

2013 ◽  
Vol 69 (11) ◽  
pp. 1411-1413 ◽  
Author(s):  
Yuko Kawanami ◽  
Hidekazu Tanaka ◽  
Jun-ichi Mizoguchi ◽  
Nobuko Kanehisa ◽  
Gaku Fukuhara ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Circular Dichroism ◽  
Carboxylic Acid ◽  
Absolute Configuration ◽  
Void Space ◽  
Circular Dichroism Spectra ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
Hydrogen Bonded

The absolute configuration has been established of the enantiopureanti-head-to-head cyclodimer of anthracene-2-carboxylic acid (AC) cocrystallized with L-propinol and dichloromethane [systematic name: (S)-2-(hydroxymethyl)pyrrolidin-1-ium (5R,6S,11R,12S)-8-carboxy-5,6,11,12-tetrahydro-5,12:6,11-bis([1,2]benzeno)dibenzo[a,e][8]annulene-2-carboxylate dichloromethane monosolvate], C5H12NO+·C30H19O4−·CH2Cl2. In the crystal structure, the AC dimer interacts with L-prolinol through a nine-membered hydrogen-bonded ring [R22(9)], while the dichloromethane molecule is incorporated to fill the void space. The absolute configuration determined in this study verifies a recent assignment made by comparing theoreticalversusexperimental circular dichroism spectra.

scholarly journals Determination of the Absolute Stereochemistry of Limonene and α-Santalol by Raman Optical Activity Spectroscopy

2012 ◽  
Vol 7 (4) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Akira Sakamoto ◽  
Nao Ohya ◽  
Toshio Hasegawa ◽  
Hiroaki Izumi ◽  
Nakako Tokita ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Optical Activity ◽  
Absolute Configuration ◽  
Natural Compounds ◽  
Vibrational Circular Dichroism ◽  
Raman Optical Activity ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
Absolute Stereochemistry

Determining the absolute stereochemistry of organic compounds in solution remains a challenge. We investigated the use of Raman optical activity (ROA) spectroscopy to address this problem. The absolute configurations of (+)-( R)- and (-)-( S)-limonene were determined by ROA spectroscopy, which can be applied to smaller amounts of sample as compared with vibrational circular dichroism (VCD) spectroscopy. This ROA method was also applied to (+)-( E)-α-santalol and shown to be successful in the determination of the absolute configuration of this compound. ROA spectroscopy shows promise as a useful tool for determining the absolute stereochemistry of many natural compounds.

Short Synthesis of Berkeleyamide D and Determination of the Absolute Configuration by the Vibrational Circular Dichroism Exciton Chirality Method

2014 ◽  
Vol 16 (5) ◽  
pp. 1386-1389 ◽  
Author(s):  
Kenta Komori ◽  
Tohru Taniguchi ◽  
Shoma Mizutani ◽  
Kenji Monde ◽  
Kouji Kuramochi ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
Vibrational Circular Dichroism ◽  
Short Synthesis ◽  
The Absolute ◽  
Circular Dichroïsm

Determination of the absolute configuration of α-amino-2-alkylthiazoles by circular dichroism

1995 ◽  
Vol 6 (9) ◽  
pp. 2145-2148 ◽  
Author(s):  
Francisco L. Merchán ◽  
Pedro Merino ◽  
Isabel Rojo ◽  
Tomás Tejero ◽  
Alessandro Dondoni
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
The Absolute ◽  
Circular Dichroïsm
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