SYNTHESIS, CRYSTAL-STRUCTURE AND CONFORMATION OF N-ACETYL-C-ALPHA,ALPHA-DIETHYLGLYCINE-N'-METHYLAMIDE

Synthesis and X-ray structure analysis of N-acetyl-C(alpha, alpha)-diethylglycine-N'-methylamide [CH3 - CO - NH - C(C2H5)2- CO - NHCH3] are described. The compound was obtained from the corresponding N-acetyl derivative [CH3 - CO - NH - C(C2H5)2 - COOH] through the mixed anhydride procedure. It crystallizes as monohydrate (C9H18N2O2.H2O) in space group P2(1)/c, a = 7.139(1), b = 11.823(2), c = 15.778(3) angstrom, beta = 122.23(1)-degrees, V= 1126.53 angstrom3, D(m) = 1.20 Mgm-3 (room temperature), R = 0.046 for 1523 reflections. The crystal packing is dominated by two strong hydrogen bonds between the water molecule and two carbonyl oxygen atoms and two weak H-bonds to two amide-N-atoms of symmetry-equivalent molecules. The molecular conformation is closer to a 3(10)-helix then an alpha-helix.