Abstract:

Twelve o-hydroxybenzyl amino acids were synthesized. Salicylaldehyde and its two derivatives were respectively condensed with each of 4-L-α-amino acids in the presence of sodium hydroxide to obtain amino acid Schiff bases, which were subsequently reduced by NaBH₄ to produce o-hydroxy benzyl amino acids(3). The structures of the products were confirmed by IR, ¹H NMR and elemental analysis. The result of preliminary bioassay shows that these compounds are highly effective in S.aureus inhibition at 0.05%(mass concentration) with an inhibitory ratio of 100% and have antibacterial activities to M.albicans and E.coli to some extent. Structure of the substituent R has important effect on the antibacterial activity of o-hydroxy-benzyl-amino acids. The effects of different alkyl R on antibacterial activities to M.albicans and E.coli show the following order CH(CH₃)₂＞CH₃， CH₂CH(CH₃)₂＞H. The bromine atoms on the benzene ring of the title compounds have little effect on antibacterial activities to M.albicans and E.coli.

Key words: Salicyladehyde, o-hydroxybenzyl-amino acid, synthesis, characterization, antibacterial activity