STRUCTURE OF N-ACETYL-L-LEUCYL-L-PROLINAMIDE MONOHYDRATE

C13H23N3O3.H2O, M(r) = 287.36, orthorhombic, P2(1)2(1)2(1), a = 6.3863 (8), b = 14.346 (2), c = 17.247 (2) angstrom, V = 1580.1 (6) angstrom 3, Z = 4, D(x) = 1.208 g cm-3, lambda(Cu K-alpha) = 1.54178 angstrom, mu = 7.04 cm-1, F(000) = 624, room temperature, final R = 0.037 for 1693 reflections with I greater-than-or-equal-to 2.5-sigma(I) and 257 variables. The peptide linkage is in a trans conformation. The pyrrolidine ring adopts a puckered C(gamma)-endo conformation and the leucine side chain is in a twisted [g-(tg-)] conformation. The crystal packing is stabilized by a three-dimensional network of hydrogen bonds which involve all the donor groups. The water molecule plays an important part in the crystal packing, being engaged in three hydrogen bonds with different N-acetylamide molecules.