Stereoselective synthesis of four stereoisomers of beta-methoxytyrosine, a component of callipeltin A.

Callipeltin A is a novel cyclic depsipeptide that selectively inhibits the cardiac sodium/calcium exchanger and is therefore of interest as a regulator of myocardial contractility. The stereochemistry of beta-methoxytyrosine, one of the amino acids contained within the marine natural product, could not be determined. In an effort to elucidate the stereochemistry of this moiety, a stereoselective synthesis of four stereoisomers of beta-methoxytyrosine from (S)- and (R)-serine was accomplished.