THE PREPARATION AND CRYSTAL-STRUCTURE OF THE 1 1-ADDUCT OF GLYCINE WITH UREA/

The 1:1 adduct of the alpha-amino acid glycine with urea has been prep ared and its crystal structure determined by X-ray crystallography and refined to a residual R 0.028 for 776 observed reflections. Crystals are monoclinic, space group P2(1), with two molecules in a cell of dim ensions a 7.364(1), b 4.8703(2), c 8.494(1) Angstrom, beta 98.555(7)de grees. The polymeric structure is based on a primary cyclic hydrogen-b onded nine-membered ring involving both the carboxyl oxygen and an ami no hydrogen of the zwitterionic glycine molecule with the urea amine h ydrogen and oxygen respectively. These repeat down the twofold screw a xis by hydrogen bonding, with additional lateral interactions completi ng the three-dimensional network structure.