Studies in molecular structure,symmetry and conformation XII: Crystal and molecular structure of D-alloisoleucine

The crystal structure of D-alloisoleucine has been determined using three-dimensional photographic data. The crystals are monoclinic:P2₁,Z= 4,a= 9.76 °,b= 5.33 Å,c=14.26 Å and β = 98.6 °. The structure was solved by packing considerations on the basis of the structure of L-isoleucine and refined by full-matrix least-squares, including anisotropic thermal parameters for all nonhydrogen atoms, to anR-factor of 0.118 for 1057 observed reflections. The two molecules in the asymmetric unit have different conformations as in the case of L-isoleucine.