Dilrukshi Vitharana

An efficient and practical direct resolution of racemic 1,1′-bi-2-naphthol to both of its pure enantiomers

Abstract An efficient and practical method to directly resolve racemic 1,1′-bi-2-naphthol, rac- 1 , into optically pure R and S- 1 has been developed by modification of a N-benzylcinchonidinium chloride resolution procedure. In a typical experiment, 60 g of rac- 1 is resolved to give 22.5 g of R- 1 (75%, >99% ee) and 21 g of S- 1 (70%, >99% ee). The chiral resolving agent, (8S, 9R)-(−)-N-benzylcinchonidinium chloride, 2 , is recovered in 80% yield.

Synthesis and biological evaluation of (R)- and (S)-2-(phosphonomethyl)pentanedioic acids as inhibitors of glutamate carboxypeptidase II

Abstract Both enantiomers of 2-(phosphonomethyl)pentanedioic acid (2-PMPA), a potent and selective inhibitor of glutamate carboxypeptidase II (GCP II), were successfully prepared through the resolution of racemic 2-(hydroxyphosphinoylmethyl)pentanedioic acid dibenzyl ester with yohimbine and (S)-α-methylbenzylamine. The enantiomeric purity of the resolved phosphinic acid was measured by coupling it to (−)-menthol and analyzing the resulting ester by 31P NMR. The absolute configuration of the 2-carbon atom in the resolved phosphinic acid was determined by X-ray crystallographic studies. Optically pure 2-PMPA was obtained by oxidation of the resolved phophinic acid to the phosphonic acid followed by catalytic hydrogenolysis. The biological activity of each enantiomer of 2-PMPA will also be described.