(2R,3R)-Allothreonine (R)-Allothreonine (R)-allo-Threonine 24830-94-2 4-04-00-03170 (Beilstein Handbook Reference) Allothreonine, D- BRN 1721644 D-Allothreonine D-allo-Threonine EINECS 246-488-0 NSC 206267