Synthesis of Some Betti Base Derivatives

Abstract

In this study, thirty one new compounds of 1- (α-aminobenzyl)-2- naphthol derivatives (Betti bases) were synthesized using two methods. In the first method, these compounds were synthesized via 1,3-naphthoxazines, by condensation reaction between β-naphthol, aromatic aldehydes and primary or secondary amines as a source of nitrogen in presence of methanol as a solvent, in the ratio of 1: 2: 1 at ambient temperature for two days. The prepared 1,3- naphthoxazines were hydrolysed in hydrochloric acid 20% with reflux for six hours to give products known as the Betti base derivatives. In the second method, Betti base derivatives were synthesized directly in one step by condensation reaction of β- naphthol, aromatic aldehydes and ammonia solution, in the presence of water as a solvent, in the ratio of 1: 1: 1 at ambient temperature with stirring for one hour. Some of the synthesized Betti base derivatives that had been coupled with benzene diazonium salts gave products in moderate to high yield as colored azo dyes. The resulting compounds were purified by recrystllization and then tested by thin-layer chromatography. Physical properties of these compounds (colour, melting point, yield in grams and percentage) and spectral properties (UV, IR, 1H-NMR and mass spectrometry) were measured. The results obtained revealed that the Betti base derivatives, whether they were synthesized either through 1,3-naphthoxazine or directly in one step gave identical spectral behavior and physical properties.