organic compounds
The preferred hydrogen-bonding patterns in eight crystal structures of 2-thiouracil derivatives were analysed. In five of the structures, the usual pairs of N—HS or N—HO hydrogen bonds are formed, whereas three structures contain `mixed' R22(8) patterns with one N—HS and one N—HO hydrogen bond.
research papers
The structures of eight benzoylhydrazones show similar conformations and hydrogen-bonding patterns. In most cases, the phenyl ring of the benzoyl group is rotated by about 30° with respect to the keto group. Only one of the amide groups exhibits the syn conformation.