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Synthesis and Antibacterial Activities of 1,4- Bissubstituted Phenyl-5-( O-hydroxyphenyl) Amino 1,2,3-triazole Compounds

Author: ZhaoZuo
Tutor: LuJunRui
School: Tianjin University of Technology
Course: Applied Chemistry
Keywords: 1-(4-substituted phenyl)- 4-substituted phenyl-5-(2-iminomethyl substituted phenol)-1,2,3-triazole 1-(4-substituted phenyl)-4-substituted phenyl-5-(2-hydroxy substituted benzyl)amino-1,2,3-triazole Synthesis characterization Antibacterial activity structure-activity relationship
CLC: TQ450.1
Type: Master's thesis
Year: 2011
Downloads: 67
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Abstract

o-hydroxy ether o-hydroxyphenyl which possessed good affinity towards pathogeny targets have the andvantige to synthesis novel antibacterial molecules. 1,2,3-triazoles possessed good biological activities, many of which are found to be potent antineoplastic, antimicrobial, analgesic, anti- inflammatory, local anesthetic, anticonvulsant, antimalarial,and anti-HIV agents. Therefore, according to the superpostion principle of reinforcement of biological activities, we want to rationally assemble the two key molecular segments“o-hydroxyphenyl”and“1,2,4-triazole together. A total of thirty seven compounds of 1-(4-Substituted phenyl)-4-(4-Substituted phenyl)-5-(2-iminomethyl halogen substituted phenol)-1,2,3-triazole and 1-(4-Substituted phenyl)-4-phenyl-5-(2-hydroxy benzyl)amino- 1,2,3-triazole which have been not reported in the literature were designed and synthesized,The inhibitory activities of all compounds were tested.Firstly, p-substituted phenyl azide were synthesized trough diazotization, and then reacted with Sodium azide by p-substituted aniline. Secondly, 1-(4-substituted phenyl)-4-(4-Substituted phenyl)-5-amino-1,2,3-triazole were prepared by p-substituted phenyl azide and p-substituted phenylacetonitrile in the presence of sodium methoxide as a catalyst. The target compounds 1-(4-Substituted phenyl)-4-(4-Substituted phenyl)-5-(2-iminomethyl halogen substituted phenol)-1,2,3-triazole were obtained by the condensation of salicylaldehyde with 1-(4-Substituted phenyl)-4-(4-Substituted phenyl)-5-amino-1,2,3-triazole, and then were deoxygenize by NaBH4 to synthesiz their corresponding deoxy compounds 1-(4-Substituted phenyl)-4-(4-Substituted phenyl)-5-(2-hydroxy substituted benzyl)amino-1,2,3-triazole. Studies have shown that p-substituted phenylacetonitrile with electron-releasing group enhance nucleophilic substitution reaction. The substituted groups in the azide group have important influence on ring closure reaction, the order of blunt: 4-Cl >4-Br >4-CH3>4-OCH3. Electronic efficiency of substituent of aromatic on triazole 1H-bit have some influence on the nucleophilic activity of amino. Electron-withdrawing group increase electron density on amino and enhance response activities, on the contrary, electron-withdrawing group decrease electron density and response activities. The experimental data showed that the order of blunt is p-Br>p-Cl>p-H>p-CH3>p-OCH3. Using NaBH4 as reducing agent would not break triazole ring due to triazole ring processing aromatic and NaBH4 owe strong selective. All compounds were characterized by 1H NMR、IR characterized to confirm.The result of antimicrobial assays showed that the all title compounds had over 80% inhibitory rate against Monilia albican and Escherichia coli at 0.01% mass concentration, had a good antibacterial activities; had over 70% inhibitory rate against Staphylococcus aureus, have a favorable extent of antibacterial activities. Especially, 1-(4-substituted phenyl)- 4-substituted phenyl-5-(2-iminomethyl substituted phenol)-1,2,3-triazole with Cl、Br had about 90% inhibitory rate against Monilia albican and Escherichia coli, some of which reach 100% inhibitory rate, had a great potential for development of anti-fungal, anti-Gram-negative bacteria compounds.The analysis of structure-activity relationship showed that antibacterial activity of compounds was related with electronic efficiency of substituent of aromatic on triazole 1H-bit, reduced by electron-releasing, such as -CH3,-OCH3, enhanced by halogen, such as Cl、Br. The reason of these may be that halogen improved the specificity of compounds with bacterial enzyme (target) and affinity. Because C = N structure made the triazole ring and phenolic hydroxyl conjugate, caused that the distribution of molecular electronic cloud tends to be delocalized and C = N structure and was easy combine with target to form molecular hydrogen bond, it enhanced antibacterial activity of compounds

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