Norleucine, a natural occurrence in a novel ergot alkaloid γ-ergokryptinine

A novel natural peptide ergot alkaloid γ-ergokryptinine containing norleucine has been isolated from ergot sclerotia of the field-growing parasitic fungus Claviceps purpurea CCM 8059. Its structure was deduced from the NMR and mass spectral data. The final structural proof was provided by the crystal structure determination, which is the first X-ray structure of a natural Nle-containing secondary metabolite. The conformations of three ergopeptinines: γ-ergokryptinine, ergoladinine, and α-ergokryptinine were compared. © Springer-Verlag 2005

Direct resolution of optically active isomers on chiral packings containingergoline skeletons. 5. enantioseparation of amino acid derivatives.

A new procedure for ergot alkaloid-based chiral stationary phase preparation is described. Synthesis is based on bonding the allyl derivative of terguride to mercaptopropylsilanized silica gel. The packing exhibits higher content of chiral selector, stability, reproducibility, and enantioselectivity toward amino acids compared to that previously studied. The chromatographic behavior of amino acids with different side chains and substituent groups is investigated in order to obtain a deeper insight into the enantiodiscriminative mechanism as well as to determine the limitations and strengths of terguride as a chiral selector for this class of compounds. A variety of factors, including mobile phase parameters such as pH, ionic strength, content and nature of organic modifier, and temperature, are examined