CONFIGURATION OF OPTICALLY-ACTIVE PHOSPHORUS THIO ACIDS .4. H-1, P-31, AND C-13 NUCLEAR MAGNETIC-RESONANCE NONEQUIVALENCE OF DIASTEREOMERIC SALTS OF CHIRAL PHOSPHORUS THIO ACIDS WITH OPTICALLY-ACTIVE AMINES - METHOD FOR DETERMINING OPTICAL PURITY AND CONFIGURATION OF CHIRAL PHOSPHORUS THIO ACIDSD

It was shown that diastereomeric salts of chiral phosphorus thio acids with optically active amines have different proton, phosphorus, and carbon NMR spectra in nonpolar solvents. The magnetic nonequivalence observed has been utilized for the first time for the direct determination of the enantiomeric content and optical purity of chiral phosphorus thio acids. In order to test the sensitivity of this method methylmethyl-d3-phosphinothioic acid and O-methyl-O-methyl-d3-phosphorothioic acid, which are chiral because of deuterium substitution, have been synthesized. The diastereomeric (-)- or (+)-1-(1-naph-thyl)ethylamine salts of both acids exhibit different 1H NMR spectra. The effect of solvent and optically active amines on the magnitude of magnetic nonequivalence, Δδ, was investigated and pyridine was found to be a very good solvent for the investigated diastereomeric salts. A correlation between the absolute configuration of O-alkylalkylphosphonothioic acids and the NMR chemical shifts of their (—)-l-phenylethylamine salts has been observed in proton and phosphorus NMR spectra. © 1978, American Chemical Society. All rights reserved.