ASYMMETRIC-SYNTHESIS OF (2S,3R)-3-AMINO-2-HYDROXYDECANOIC ACID - THE UNKNOWN AMINO-ACID COMPONENT OF MICROGININ

3-Amino-2-hydroxydecanoic acid (AHDA) is an unusual amino acid purport ed to occur in the recently isolated angiotensin-converting enzyme inh ibitor microginin. In order to elucidate the stereochemistry of the na turally occurring material, and thus complete the structural assignmen t of microginin, both the (2R,3R)-anti-diastereoisomer and the (2S,3R) -syn-diastereoisomer of AHDA have been prepared. Comparison of the H-1 and C-13 nmr spectroscopic data of the synthetic amino acids with tha t reported for the naturally occurring material indicates that the rel ative stereochemistry of the AHDA found in microginin is syn. The abso lute stereochemistry of the natural amino acid is shown to be (2S,3R) by comparison of its reported CD spectrum with that recorded for the s ynthetic material prepared herein.