Structure of 5-fl-D-Galactopyranosyl- 1,3-dimethylbarbituric Acid Monohydrate,* C12H1sN2Os.H20

Mr=336'30, orthorhombic, P21212 ~, a= 9.147(1), b=23.054(2), c=6.921(1)A, V= 1459.5(3)A 3, Z=4, Dm=l'53(1), Dx= 1.531Mgm -3, MoKa, 2=0.7107A, #=0.12mm -1, F(000)= 712, T= 300K, R =0.055 for 1623 observed independent reflexions. The galactopyranose ring adopts a 4C l conformation and the dihedral angle between the two rings in the molecule is 89.1 (1) °. The molecules are linked by an extensive three-dimensional hydrogen-bond network involving the water hydration molecule which stabilizes the crystal structure.