Synthesis of some new anils: part 1. Reaction of 2-hydroxy-benzaldehyde and 2-hydroxynaphthaldehyde with 2-aminopyridene and 2-aminopyrazine.
New Schiff bases derived from 2-aminopyridene and 2-aminopyrazine have been synthesized. The UV-Visible spectra of the compounds have been investigated in acetonitrile and toluene. The compounds were in tautomeric equilibrium (enol-imine O- H...N, keto-amine O...H-N forms) in polar and nonpolar solvents. For some derivatives the keto-amine form was observed in both toluene and acetonitrile. 1H-NMR and IR results showed that all Schiff bases studied favor the enol-imine form over the keto form in a weakly polar solvent such as deuterochloroform.
4-[(2-Hydroxy-1-naphthyl)methylideneamino]benzoic acid
The molecule of the title compound, C18H13NO3, is almost planar, the dihedral angle between the naphthalene and benzene ring systems being 4.04 (6)°. The molecular conformation and packing are stabilized by intramolecular O—H⋯N and intermolecular O—H⋯O and C—H⋯O interactions.
Phloroglucinol derivatives from Hypericum japonicum.
The isolation and identification of a new phloroglucinol derivative (2), a diterpenol (4), together with the known compounds flavesone (1) and sarothralen B (3), from the aerial parts of Hypericum japonicum are reported. Their structures were established by extensive spectral analysis and the structure of (3) has also been confirmed by a single crystal X-ray determination.