Structure of 5-(p-n-Glucopyranosyl)barbituric Acid Trihydrat

Abstract

C 1oH15N 307.3H20, M,= 343·3, monoclinic, P21, a= 10·883 (3), b = 12·497 (20), e=rings for the two molecules are 80·9 (3) and 90·3 (3)0 • The molecules are linked by an extensive three­10·553 (4)Á, {3= 91·05 (3)0 , V= 1435 (2)Á3 Z=4, dimensional hydrogen-bonding network, involving the Dm = 1·57 (2), Dx = 1·589 Mg m-3, Mo Ka, A.= 0·7107 Á, 11 = 0·13 mm-t, F(OOO) = 728, T= 300 K, R = 0·064 for 2692 observed independent refl.exions. The compound presents a zwitterionic structure in which the negative charge is delocalized in the system formed by the two carbonyl groups at C4 and C6 and the carbon atom e5 of the barbituric ring. In the two independent molecules in the asymmetric unit the pyranose ring adopts a 4C1 conformation and the dihedral angles between the pyranose and barbituric water hydration molecules, which stabilize the crystal structure.