MalphaNP acid (+/-)-1, 2-methoxy-2-(1-naphthyl)propionic acid, was enantioresolved by the use of phenylalaninol (S)-(-)-4; a diastereomeric mixture of amides formed from acid (+/-)-1 and amine (S)-(-)-4 was easily separated by fractional recrystallization and/or HPLC on silica gel, yielding amides (R;S)-(-)-5a and (S;S)-(+)-5b. Their absolute configurations were determined by X-ray crystallography by reference to the S configuration of the phenylalaninol moiety. Amide (R;S)-(-)-5a was converted to oxazoline (R;S)-(+)-8a, from which enantiopure MalphaNP acid (R)-(-)-1 was recovered. In a similar way, enantiopure MalphaNP acid (S)-(+)-1 was obtained from amide (S;S)-(+)-5b. These reactions provide a new route for the large-scale preparation of enantiopure MalphaNP acid, a powerful chiral reagent for the enantioresolution of alcohols and simultaneous determination of their absolute configurations by (1)H NMR anisotropy.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/chir.20385 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Chiral organic stereochemistry: Chiral HPLC, chiral auxiliaries, CD spectroscopy, X-ray crystallography, and light-powered chiral molecular motors.
Chirality
February 2022
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan.
In the studies of chiral organic stereochemistry, it is important to use enantiopure compounds. For this purpose, the chiral HPLC (High-Pressure Liquid Chromatography) columns containing chiral stationary phases were invented by Y. Okamoto and coworkers for enantio-separating various racemic compounds.
View Article and Find Full Text PDFChiral Molecular Science: How were the absolute configurations of chiral molecules determined? "Experimental results and theories".
Chirality
December 2017
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University Sendai, Japan.
Molecular chirality is a key concept in chemistry, bioscience, and molecular technology, like the invention of a light-powered chiral molecular motor explained in this review. Thus, the primary research subject is how to determine the absolute configuration (AC) of chiral compounds. This review article focuses on the principle, theory, and practice of the nonempirical methods for determining ACs of chiral compounds, i.
View Article and Find Full Text PDFReinvestigation of the Absolute Configurations of Chiral β-Mercaptoalkanones Using Vibrational Circular Dichroism and H NMR Analysis.
J Agric Food Chem
November 2016
Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universität München, Maximus-von-Imhof-Forum 2, D-85354 Freising-Weihenstephan, Germany.
The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones.
View Article and Find Full Text PDFHPLC Separation of Diastereomers: Chiral Molecular Tools Useful for the Preparation of Enantiopure Compounds and Simultaneous Determination of Their Absolute Configurations.
Molecules
October 2016
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan.
To obtain enantiopure compounds, the so-called chiral high performance liquid chromatography (HPLC) method, i.e., HPLC using a chiral stationary phase, is very useful, as reviewed in the present Special Issue.
View Article and Find Full Text PDFNaphthyl groups in chiral recognition: structures of salts and esters of 2-methoxy-2-naphthylpropanoic acids.
Chem Asian J
October 2012
Division of Insect Sciences, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8634, Japan.
The crystal structures of salt 8, which was prepared from (R)-2-methoxy-2-(2-naphthyl)propanoic acid ((R)-MβNP acid, (R)-2) and (R)-1-phenylethylamine ((R)-PEA, (R)-6), and salt 9, which was prepared from (R)-2-methoxy-2-(1-naphthyl)propanoic acid ((R)-MαNP acid, (R)-1) and (R)-1-(p-tolyl)ethylamine ((R)-TEA, (R)-7), were determined by X-ray crystallography. The MβNP and MαNP anions formed ion-pairs with the PEA and TEA cations, respectively, through a methoxy-group-assisted salt bridge and aromatic CH⋅⋅⋅π interactions. The networks of salt bridges formed 2(1) columns in both salts.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!