Figure 1
Molecular structures of the title compounds (I)–(IV), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. In the hydrogen bonds between the carboxy group and the N atom of the base of compounds (I), (III) and (IV), the H atoms are each disordered over two positions. Dashed lines in (II) and (III) indicate the O—H⋯N and C—H⋯O hydrogen bonds. |