Arzanol is a naturally-occurring prenylated acylphloroglucinol isolated from Helichrysum italicum and exhibiting anti-oxidant, antibiotic and antiviral activities. The molecule contains an α-pyrone moiety attached to the phloroglucinol moiety through a methylene bridge. The presence of several hydrogen bond donor or acceptor sites makes intramolecular hydrogen bonding patterns the dominant stab...

In the crystal structure of the title compound, C(9)H(10)O(4)S, centrosymmetrically related mol-ecules are linked into dimers by inter-molecular O-H⋯O hydrogen bonds. Unconventional C-H⋯O hydrogen-bond inter-actions are also present, connecting dimers into a three-dimensional network.

bonds [either N–H···O (keto-amine tautomer) or N···H–O (phenol-imine tautomer)] can exist. It is claimed that the hydrogen-bond type depends neither on the stereochemistry of the molecule nor on the sort of substituent bonded to the N imino atom, but on the kind of aldehyde used.1 In the solid state, it is also claimed that only an intramolecular N–H···O type hydrogen bond is present in naphtha...

The association of substituted benzoates and naphthyridine dianions was used to study the complexation of dibutyltriuret. The title molecule is the simplest molecule able to form two intramolecular hydrogen bonds. The naphthyridine salt was used to break two intramolecular hydrogen bonds at a time while with the use of substituted benzoates the systematic approach to study association was achie...

In the title racemic compound, C(26)H(32)N(2)O(3), an intra-molecular O-H⋯N hydrogen bond is formed between the phenolic OH group and the tertiary amine N atom. Another O-H⋯N hydrogen bond that is formed between the OH group and the pyridine N atom links the mol-ecules into a polymeric chain extending along the a axis. The structure is further stabilized by intramolecular and intermolecular C-H...

The mol-ecule of the title compound, C(15)H(14)N(2)O(4), displays a trans configuration with respect to the hydrazide C=N bond. The dihedral angle between the two benzene rings is 15.0 (2)°. In the crystal structure, mol-ecules are linked through inter-molecular O-H⋯N and O-H⋯O hydrogen bonds, forming layers parallel to the ab plane; an intramolecular N-H⋯O hydrogen bond is also present.

The molecule of the title compound, C(15)H(16)N(2)O, is non-planar with a dihedral angle of 16.0 (1)° between the pyrrole and benzene rings. The ketone double-bond displays an s-cis conformation with an O=C-C=C torsion angle of 7.9 (3) and an intramolecular C-H⋯O hydrogen bond. In the crystal structure, adjacent mol-ecules are paired through N-H⋯O hydrogen bonds into centrosymmetric dimers.

The title compound, C(10)H(12)N(2)O(4), adopts a trans configuration with respect to the C=N bond. The hydrazinecarboxyl-ate group is twisted from the benzene ring by 6.62 (5)° and an intramolecular O-H⋯O hydrogen bond occurs. In the crystal structure, mol-ecules are linked into a two-dimensional network parallel to (100) by O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds. In addition, weak C-H⋯π inter-a...