Two diasteoisomers of 5-hydroxy-6-methylpipecolic acid from seeds of Fagus silvatica L.

Two diastereoisomers of 5-hydroxy-6-methylpipecolic acid have been isolated from beechnuts. The configurations of the two amino acids have been assigned as (2S, 5S, 6S) (1) and (2S, 5R, 6S) (2). The determination of structure and configuration for the two new amino acids is mainly based on spectroscopic and rotatory evidence. The ¹³C-NMR and ¹H-NMR spectra of the three ionic forms of the two amino acids and of S-pipecolic acid and (2S, 5R)-5-hydroxypipecolic acid and the CD-curves of the cations and amfoions of 1, 2, and (2S, 5R)-5-hydroxypipecolic acid have been recorded.