Two families of regioisomeric 1,4-benzodiazepines, 4-benzyl-3H-benzo[e][1,4]diazepin-5-ones and 4-benzoyl-4,5-dihydro-3H-benzo[e][1,4]diazepines, have been synthesized through a similar Ugi/reduction cyclization sequence. Their conformation and stability depend on the position of the tautomeric imine/enamine equilibrium present in the diazepine nucleus, which in turn depends on the relative pos...

The results of geometry optimisation of possible Watson-Crick-like pairs of 2,6-diamino-4-oxy-5-formamidopyrimidine (fapy-adenine) or 4,6-diamino-5-formamidopyrimidine (fapy-guanine) were presented. In the absence of the external field the fapy-adenine is able to form pairs with all four canonical nucleic acid bases. However, pairs with guanine, cytosine and thymine the most stable are. Thus, t...

We report the photoelectron spectrum of the 6-azauracil anion. The spectrum is dominated by a broad band exhibiting a maximum at an electron binding energy (EBE) of 1.2 eV. This spectral pattern is indicative of a valence anion. Our calculations were carried out using ab initio electron propagator and other many-body methods. Comparison of the anion and corresponding neutral of 6-azauracil with...

Tautomeric rearrangements of a molecule lead to distinct equilibrated structural states of the same chemical compound that may differ significantly in molecular shape, surface, nature of functional groups, hydrogenbonding pattern and other derived molecular properties [1]. Especially for the structure-based pharmacophore modeling of ligand-protein complexes [2], knowledge of the most favorable ...

The title compound, C(12)H(14)ClN(3), represents the planar azoenamine tautomer. The benzene ring forms a dihedral angle of 2.5 (1)° with the azoenamine group. Electron delocalization is indicated by the values of the bond lengths in the chain. The tetra-hydro-pyridine ring adopts a half-chair conformation and the dihedral angle between the least-squares plane defined by the five coplanar C ato...

The title compound, C(17)H(19)NO(2), exists as an enol-imine tautomer. The dihedral angle between the two benzene rings is 4.6 (2)°. The mol-ecular structure is stabilized by intramol-ecular O-H⋯O and O-H⋯N hydrogen bonds which generate S(5) and S(6) ring motifs, respectively. In the crystal, mol-ecules are linked into centrosymmetric dimers by pairs of O-H⋯O hydrogen bonds. In addition, C-H⋯π ...

The title compound, C(17)H(12)N(2)O(3), was synthesized by the reaction of 2-hy-droxy-1-naphthaldehyde with 4-nitro-benzenamine. These condense to form the Schiff base, which crystallizes in the zwitterionic form. In the structure, the keto-amino tautomer has a fairly short intra-molecular N-H⋯O hydrogen bond between the 2-naphthalenone and amino groups, with electron delocalization. The mol-ec...