Schiff Base Of Several Benzaldehydes

Schiff bases and their metal complexes are very important compounds because their core group C=N has chemical and biological significance. Hitherto, research work about this field is being done by researchers in the world, who have synthesized and estimated a plenty of Schiff bases and their metal complexes, studied and exploited many uses, such as catalyst, antibacterial medicines, material, etc.The alcohol amine compounds, fluoride and thiosemicarbazide containing labile amine group, hydroxyl group, fluorine atom and sulphur atom which can influence the chemical property and biological activity of compounds tremendously were applied to drug, pesticide and organic intermediate extensively. The last few years, they have become the most challenging building blocks for chemistry.In this paper, we chose benzaldehyde with electron withdrawing group or donor group, alcohol amine and thiosemicarbazide. Eight Schiff bases have been synthesized directly and five of them have not been reported by literatures. The rate of alcohol amine Schiff bases and 3,4,5-trimethoxybenzylideno monothiosemicarbazide is high. Melting Point, IR, Mass spectrum and elemental analyses have been performed about 2-hydroxy-1,3,5-benzenetricarbaldehyde monoethanolamine, 2-hydroxy-1,3,5-benzenetricarbaldehyde triethanolamine, 2-hydroxy-1,3,5-benzenetricarbaldehyde monopropanolamine, 3,4,5-trimethoxybenzylideno monothiosemicarbazide, p-fluorobenzylidene monothiosemicarbazide, 2-4[(fluorobenzylidene)-amino]-propanol. Their structures and compositions are in agreement with targets.The antibacterial activities of the Schiff bases have been tested against gram-positive (Staphylococcus aureus, Bacillus subtilis) and gram-negativebacterium (Escherichia coli). The international codex current method (pipe-plate method or cup-plate method) was used. The inhibition curves were drew by datum of zone of inhibition. We found that these Schiff bases had antibacterial activity. Among these compounds, Schiff bases containing fluorine atom markedly inhibited bacteria from breeding. Schiff bases with unsubstitutional amine group had higher activity than those without unsubstitutional amine group. Schiff bases had lower antibacterial activities in inhibiting Escherichia coli than in inhibiting Staphylococcus aureus and Bacillus subtilis. Antibacterial activity mechanism was predicted.