On the Use of O-Methylmandelic Acid for the Establishment of Absolute Configuration of .alpha.-Chiral Primary Amines

Assignment of absolute configuration of 3‐hydroxy β‐lactams by the NMR “mix and shake” method

“…This situation is beautifully reflected in the NMR spectra. The assignment of absolute configuration was based on the configurational model for ester derivatives 5,6,15,16 and provided results which were in agreement with independently obtained (X-ray crystal structure analyses) configurations of these compounds. Here, we focused our attention on the proton shift for the H 1 (Scheme 1) on the lactam ring.…”

Identification of the Absolute Configuration of Pectenotoxin-6, a Polyether Macrolide Compound, by NMR Spectroscopic Method Using a Chiral Anisotropic Reagent, Phenylglycine Methyl Ester

“…However, we presumed that the electrostatic repulsion between the lone pair electrons of the ether oxygen 0-18 and carbonyl oxygen C43 0 will make PGME in PTX6-(~)-or PTX6-(S)-PGME amide to take the same conformatIOn as was proven in the literature. 8,9) Hence, the phenyl group of PGME was predicted to exert its diamagnetic field effectively upon protons adjacent to the chiral C-18 carbon. This report deals with identification of the absolute configuration of 4 by using PGME as the chiral anisotropic reagent.…”

Enantiomeric separation and determination of absolute stereochemistry of asymmetric molecules in drug discovery—Building chiral technology toolboxes

“…[198][199][200][201][202][203] These and structurally-related acids as well as several types of optically-active alcohols have found great utility to determine the absolute stereochemistry of enantiomerically pure or enriched secondary alcohols [353][354][355][356][357][358] and diols, 359,360 b-chiral alcohols, 361,362 a-chiral amines, [363][364][365][366][367] mixed chiral amines and alcohols, 368,369 chiral carboxylic acids, [370][371][372] and chiral 3-hydroxy b-lactams. 373 These reagents have also found combined utility in enantiomeric separation, including LC-NMR, plus determination of absolute stereochemistry of various types of compounds such as diastereomeric alcohols [374][375][376][377] and 2-hydroxypyrrolizidinones.…”