CRYSTAL-STRUCTURE AND CONFORMATION OF N-(T-BUTOXYCARBONYL)-L-ISOLEUCYL-L-ALANINE BENZYLESTER

C22N205H32, M(r) = 404.5, monoclinic, C2, a = 21.781(5), b = 5.065(1), c = 22.333(4) angstrom, beta = 112.81(2)-degrees, V = 2271.1(9) angstrom3, D(calc) = 1.148g cm-3, lambda(Cu K(alpha)) = 1.5418 angstrom, mu = 5.89 cm-1, F(000) = 848, room temperature, R = 0.058 for 2178 unique reflections [I greater-than-or-equal-to 2.5sigma(I)]. The peptide linkage is in the trans conformation. The molecule adopts the beta-sheet structure. The crystal structure is stabilized by a three-dimensional network of N-H...O and C-H...O hydrogen bonds.