In the title compound, C(11)H(10)ClNO(3), the dihedral angle between the benzene ring and the amide group is 6.6 (10)° and an intramolecular O-H⋯O hydrogen bond occurs. In the crystal, molecules are linked by N-H⋯O hydrogen bonds, generating C(7) zigzag chains.

In the crystal structure of the title compound, C(10)H(8)BrN(3)O, the dihedral angle between the two pyridine rings is 2.48 (2)°. A weak intramolecular N-H⋯O hydrogen bond is present.

In the title compound, C(21)H(16)N(2)O, the dihedral angle between the pendant aromatic rings is 74.2-(1)°.. The conformation is stabilized by an intramolecular O-H⋯N hydrogen bond.

The title compound, C(12)H(21)NO(4), a γ-aminobutyric acid derivative, crystallizes with two mol-ecules in the asymmetric unit. The crystal structure is stabilized by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds, forming a strand. An intramolecular N-H⋯O hydrogen bond is also observed.

The molecule of the title compound, C(13)H(10)N(2)O(4), is nearly planar with a dihedral angle between the two aromatic rings of 2.24 (9)°. The NH group forms an intramolecular hydrogen bond with the carbonyl O atom. The mol-ecules form dimers about inversion centers in the crystal structure via inter-molecular O-H⋯O hydrogen bonds.

The mol-ecular conformation of the title compound, C(10)H(13)N(3)O(2)S, is stabilized by an intramolecular O-H⋯N hydrogen bond. Adjacent mol-ecules are linked by O-H⋯O hydrogen bonds to furnish a zigzag chain.

Approximate ab initio molecular orbital methods are used to examine the structural and electronic properties of oxymorphone. The most stable conformation of the molecule is found to include an intramolecular hydrogen bond between the C-14 hydroxyl group and the nitrogen atom in agreement with available experimental data. The total molecular electron density is transformed to a set of localized ...

The conformational stability of hexahydropyridobenzodioxin and related derivatives in both protonated and non-protonated forms have been investigated by means of ab initio molecular orbital methods as well as semi-empirical AM1 and PM3 methods. One of the cis conformers (cis2e) has been found to be most stable due to the formation of an intramolecular hydrogen bond, other conformers including t...

In mol-ecule of the title compound, C(16)H(14)N(2)O(2), the two aromatic rings form a dihedral angle of 6.93 (3)° and an intramolecular N-H⋯O hydrogen bond occurs. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into zigzag chains running in the [10] direction.

The vicinity of a hydrogen bond donor (O–H) and a hydrogen bond acceptor (C=O or C=N– R) in salicylaldehydes and ortho-Schiff bases results in significant structural variations compared to the monosubstituted derivatives that are reflected in the electronic structure and thus in the spectroscopic properties. This interplay between intramolecular hydrogen bonding and multicenter πelectron deloca...