Synthesis of N-[(3-Amino-1,2-dicarba-closo-dodecaboran-1-yl)acetyl] Derivatives of α-Amino Acids

2007 ◽  
Vol 72 (12) ◽  
pp. 1697-1706 ◽  
Author(s):  
Galina L. Levit ◽  
Victor P. Krasnov ◽  
Dmitriy A. Gruzdev ◽  
Alexander M. Demin ◽  
Iliya V. Bazhov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Alkyl Esters ◽  
X Ray ◽  
X Ray Crystallography ◽  
Carbodiimide Method ◽  
The Absolute ◽  
Derivatives Of

The N-[(3-amino-1,2-dicarba-closo-dodecaboran-1-yl)acetyl] derivatives of α-amino acids were prepared starting from N-protected (Ac, Form, Bz, and Boc) 3-amino-1-(carboxymethyl)-o-carboranes and alkyl esters of natural α-amino acids using the carbodiimide method of coupling and removing the ester groups. All the amides obtained were diastereoisomeric mixtures. Some diastereoisomers were separated and the assignment of the absolute configuration of aminocarborane fragments was performed by X-ray crystallography.

The synergy of different solid-state techniques to elucidate the supramolecular assembly of two 1H-benzotriazole polymorphs

2019 ◽  
Vol 21 (36) ◽  
pp. 19879-19889
Author(s):  
María Mar Quesada-Moreno ◽  
Juan Ramón Avilés-Moreno ◽  
Juan Jesús López-González ◽  
Fco. Javier Zúñiga ◽  
Dolores Santa María ◽  
...  
Keyword(s):  
Solid State ◽  
Quantum Chemical Calculations ◽  
Absolute Configuration ◽  
Quantum Chemical ◽  
Supramolecular Structure ◽  
Supramolecular Assembly ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Absolute

4aα (chiral) and 4aβ (achiral) polymorphs of 1H-benzotriazole are studied by X-ray crystallography, SSNMR, IR, Raman, VCD, and quantum chemical calculations. The absolute configuration of the supramolecular structure of 4aα polymorph is determined.

Conclusive Determination of the Absolute Configuration of Chiral C60-Fullerenecis-3 Bisadducts by X-ray Crystallography and Circular Dichroism

2005 ◽  
Vol 117 (15) ◽  
pp. 2302-2305 ◽  
Author(s):  
Shunsuke Kuwahara ◽  
Kazuhiro Obata ◽  
Kazuhiro Yoshida ◽  
Takatoshi Matsumoto ◽  
Nobuyuki Harada ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Absolute ◽  
Circular Dichroïsm

scholarly journals Synthesis of enantiomerically enriched (R)-13C-labelled 2-aminoisobutyric acid (Aib) by conformational memory in the alkylation of a derivative of L-alanine

2011 ◽  
Vol 7 ◽  
pp. 1304-1309 ◽  
Author(s):  
Stephen P Fletcher ◽  
Jordi Solà ◽  
Dean Holt ◽  
Robert A Brown ◽  
Jonathan Clayden
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Enantiomeric Purity ◽  
Methyl Groups ◽  
Aminoisobutyric Acid ◽  
The Absolute ◽  
Conformational Memory ◽  
Enantioselective Alkylation ◽  
Derivatives Of

The method of Kouklovsky and coworkers for the enantioselective alkylation of cyclic N-naphthoyl derivatives of amino acids was used to introduce a 13C label into one of the two enantiotopic methyl groups of 2-aminoisobutyric acid (Aib) by retentive alkylation of L-alanine with 13CH3I. Conditions were identified for optimization of yield and enantiomeric purity, and the absolute configuration of the labelled product was established.

Synthese und absolute Konfiguration kettenverzweigter, Cimetidin-analoger Thioether / Synthesis and Absolute Configuration of Chain Branched Cimetidine Analogous Thioethers

1987 ◽  
Vol 42 (3) ◽  
pp. 348-354 ◽  
Author(s):  
Sigurd Elza ◽  
Martin Dräger ◽  
Walter Schunack
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Enantiomeric Excess ◽  
Building Blocks ◽  
Anomalous Dispersion ◽  
X Ray Diffraction ◽  
Enantiomerically Pure ◽  
X Ray ◽  
The Absolute ◽  
Branched Compound

Chain branched Cimetidine analogous thioethers, promising building blocks for the preparation of H2-histaminergic compounds, were synthetized from chiral aminoalkanethiols. Enantiomerically pure amino acids or aminoalcohols were used as starting materials. In one case, a resolution via neutral and acid di-O-(4-toluoyl)tartrates was achieved in good yields and satisfying enantiomeric excess. The absolute configuration of an ethyl branched compound was determined using X-ray diffraction and anomalous dispersion

Structures and Synthesis of 4a-Homo-7,19-dinorsteroids, X-Ray Crystallography and NMR Spectroscopy

1999 ◽  
Vol 64 (12) ◽  
pp. 2019-2034 ◽  
Author(s):  
Alexander Kasal ◽  
Miloš Buděšínský ◽  
Jan Pelnař ◽  
Michael A. Bruck ◽  
Michael F. Brown
Keyword(s):  
Nmr Spectroscopy ◽  
Absolute Configuration ◽  
Starting Material ◽  
Nmr Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Leaving Group ◽  
The Absolute ◽  
Related Compounds

X-Ray diffraction revealed the absolute configuration of 4aβ-methyl-4a-homo-7,19-dinor- 5α,10α-androstane-3,17-dione. Detailed NMR analysis suggested that the 5α configuration existed in the starting material, 3β-acetoxy-4a-methylidene-4a-homo-7,19-dinor- 5α-androst-9-en-17-one, and related compounds. Thus 5-methyl-5β-estr-9-ene derivatives with a leaving group in position 6β were found to react with nucleophiles to form rearranged 4a-homo-7,19-dinorandrostane derivatives with a 5α configuration.

scholarly journals Ferrocene derivatives of liquid chiral molecules allow assignment of absolute configuration by X-ray crystallography

2017 ◽  
Vol 28 (10) ◽  
pp. 1321-1329 ◽  
Author(s):  
Philipp M. Holstein ◽  
Julian J. Holstein ◽  
Eduardo C. Escudero-Adán ◽  
Olivier Baudoin ◽  
Antonio M. Echavarren
Keyword(s):  
Absolute Configuration ◽  
Chiral Molecules ◽  
Ferrocene Derivatives ◽  
X Ray ◽  
X Ray Crystallography ◽  
Derivatives Of

Conclusive Determination of the Absolute Configuration of Chiral C60-Fullerenecis-3 Bisadducts by X-ray Crystallography and Circular Dichroism

2005 ◽  
Vol 44 (15) ◽  
pp. 2262-2265 ◽  
Author(s):  
Shunsuke Kuwahara ◽  
Kazuhiro Obata ◽  
Kazuhiro Yoshida ◽  
Takatoshi Matsumoto ◽  
Nobuyuki Harada ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Absolute Configuration ◽  
X Ray ◽  
X Ray Crystallography ◽  
The Absolute ◽  
Circular Dichroïsm

Determination of the Complete Absolute Configuration of Petriellin A

2006 ◽  
Vol 59 (6) ◽  
pp. 407 ◽  
Author(s):  
Luigi Aurelio ◽  
Robert T. C. Brownlee ◽  
Jason Dang ◽  
Andrew B. Hughes ◽  
Gideon M. Polya
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Natural Product ◽  
Absolute Configuration ◽  
Structural Determination ◽  
Amino Acid Residues ◽  
The Common ◽  
The Absolute ◽  
Derivatives Of

We report the full structural determination of the depsipeptide petriellin A. The absolute configuration of the amino acid residues, N-methyl isoleucine and N-methyl threonine, have been determined by a combination of HPLC and TLC comparison of synthetic Marfey’s derivatives and Marfey’s derivatives of the natural product hydrolysate. The configuration of the chiral centres in these two N-methylated residues was found to be the same as those of the common unmethylated l-amino acids.

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