1,2-DIHYDROXY-ETHANE-1,2-DIPHOSPHONIC ACID DERIVATIVES: STEREOCHEMICAL INVESTIGATIONS BY NMR METHODS

Abstract

A variety of NMR spectroscopic methods has been used to investigate the stereochemistry of a series of derivatives of 1,2-dihydroxy-ethane-1,2-diphosphonic acid, a structural analogue of tartaric acid. These derivatives are prepared by diastereospecific reactions of P(O)H compounds with glyoxal. ¹H, ¹³C, and ³¹P spectra using single and double resonance techniques have been measured for eight typical derivatives 1–8.

In the case of the tetramethyl ester both diastereomers 2a and 2b were available, and they have been distinguished by measurement of coupling constants ³J_pp and ³ _HH as well as by measuring the proton decoupled ³¹P NMR spectrum in the presence of a chiral additive, L(+)-dibenzoyltartaric acid.

Both meso and racemic forms 2a and 2b have the two phosphonic acid groups in an anti-periplanar arrangement, as do all the other derivatives 1, 3–8 we have studied.

Key Words:

• 1,2-Dihydroxy-ethane-1,2-diphosphonic acid
• stereochemistry
• NMR