Chiral diamine-derived hydrogen-bond donors were evaluated for their ability to effect stereocontrol in an intramolecular hetero-Diels-Alder (HDA) reaction hypothesized in the biosynthesis of brevianamides A and B. Collectively, these results provide proof of principle that small-molecule hydrogen-bond catalysis, if even based on a hypothetical biosynthesis construct, holds significant potentia...

In the title compound, C(21)H(21)N(3)O(2), the pyridine rings and the benzene ring lie in a propeller arrangement around the central tertiary amine N atom. The dihedral angles formed by the benzene ring with the pyridine rings are 61.0 (3) and 49.6 (3)°, while the dihedral angle between the pyridine rings is 69.7 (3)°. The mol-ecular conformation is stabilized by intramolecular bifurcated O-H⋯N...

A "V"-shaped Hammett plot shows that resonance-assisted hydrogen bonding does not dictate the strength of the intramolecular hydrogen bond in the E isomers of hydrazone-based switches because it involves an aromatic pyridyl ring.

The synthesis and physicochemical properties of a range of 2- and 6-amido-3-hydroxypyridin-4-ones are described. All the amido-substituted 3-hydroxypyridin-4-ones have lower pK(a) values than 1,2-dimethyl-3-hydroxypyridin-4-one (deferiprone). This is due to the inductive effect of the amido group. Furthermore, the pK(a) values of the 3-hydroxy group in 1-nonsubstituted pyridinones are dramatica...

Intramolecular hydrogen bond (HB) formation was analyzed in the model compounds N-(2-benzoylphenyl)acetamide, N-(2-benzoylphenyl)oxalamate and N1,N2-bis(2-benzoylphenyl)oxalamide. The formation of three-center hydrogen bonds in oxalyl derivatives was demonstrated in the solid state by the X-ray diffraction analysis of the geometric parameters associated with the molecular structures. The solven...

The main mol-ecule of the title methanol solvate, C(16)H(10)Cl(2)N(2)O·CH(3)OH, exists in the keto form and the C=O and N-H bonds are mutually cis in the crystal structure. The dihedral angle between the quinoline and benzene rings is 11.17 (3)°. A bifurcated intra-molecular N-H⋯(O,N) hydrogen bond is present as well as an O-H⋯O hydrogen bond. In the crystal, C-H⋯O inter-actions link the 3,5-di...

The title compound, C(19)H(19)ClO(5), is a chloro derivative of a biologically significant chalcone family. The mean plane of the two substituted benzene rings are twisted by 55.33 (8)° with respect to each other. An intra-molecular C-H⋯Cl hydrogen bond generates an S(5) graph-set motif. In the crystal, a bifurcated O-H⋯(O,O) hydrogen bond leads to an R(1) (2)(5) graph-set motif and to the form...

In t the title compound, C(14)H(12)BrN(3)O(2). H(2)O, the conformation of the C=N double bond in the hydrazide Schiff base mol-ecule is E. The dihedral angle between the benzene rings is 48.01 (11) °. An intra-molecular O-H⋯N hydrogen bond makes an S(6) ring motif. In the crystal, mol-ecules are linked through N-H⋯O (bifurcated acceptor) and O-H⋯O hydrogen bonds, forming two-dimensional network...

In the title compound, C15H11F3N2O4, the N=C bond of the central imine group adopts an E conformation. The dihedral angle between two benzene rings is 6.2 (2)°. There is an intra-molecular bifurcated O-H⋯(N,O) hydrogen bond with S(6) and S(9) ring motifs. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds into a helical chain along the 31 screw axis parallel to c. The -CF3 group show...

In the crystal structure of the title salt, C(8)H(8)NO(2) (+)·I(-), the cations and anions are linked by bifurcated N-H⋯(O,I) hydrogen bonds. A near-linear O-H⋯I hydrogen bond also exists between the cation and anion, resulting in a two-dimensional network. In the cation, the carboxyl group is twisted with respect to the pyridine ring at a dihedral angle of 15.34 (17)°.