Abstract:
The first part of a the thesis consists of theory and literature survey of Naphthoxazine and Betti bases.
Naphthoxazine derivatives can be used as intermediates in the synthesis of N-substituted aminoalcohols or in enantioselective syntheses of chiral amines. In recent times, the racemic Betti base was used only for the transformation into products showing antibacterial activity.
The 1,3-diphenyl-2,3-dihydro-1H- naphth[1,2-e][1,3]oxazine reaction was performed by mixing 1:2 molar amounts of methanolic ammonia solution (25%) and benzaldehyde and subsequent addition of 2-naphthol in a sufficient amount of methanol at ambient temperature for 48 hours.
2-naphthol Mannich bases (Betti bases) were synthesized using two different approaches. The main distinctive features of these aminonaphthols are represented by an economical and simple synthesis (Betti reaction), involving cheap starting materials. The first procedure, involving two steps starting from β-naphthol, derivatives of benzaldehyde and ammonia to give a product with the ratio of 1:2:1 respectively. The product was identified as 1,3-disubstituted-2,3-dihydro-1H- naphth[1,2-e][1,3]oxazine (II, III and IV). Subsequent treatment of (II and IV) with 20% HCl, followed by addition of ammonia solution to the ammonium salt, yielding 1-(α-amino benzyl)-2-naphthol (V and VI). A second procedure which compromises the issues of Green and Click chemistry, is a condensation of β-naphthol, benzaldehyde and ammonia in water at ambient temperature, it is a quick, convenient and efficient method. Compared with the first procedure, the method has the advantages of omitting organic solvent, generality and simplicity of procedure, low reaction time, and obtaining excellent yield.
Their N-acylated and alkylated derivatives were also synthesized following Schotton-Baumann reaction. N,N-dimethyl derivative was resolved into the two enantiomers with an extremely easy and efficient procedure. As an extension of the modified three component Mannich reaction, derivatives of benzaldehde and dimethyl amine have been used.The reactions mechanism and retrosynthetic analysis pathway were discussed in part three of the thesis. Structures of the synthesized compounds were confirmed by UV, IR, and 1H NMR. In addition to, the compounds (II-XI) were tested for antimicrobial activity against standard microbial and fungal organisms.