N,N'-二(2-羟苄基)取代咪唑烷的合成、表征及抑菌活性

利用生物活性叠加原理,将"邻羟苯基"和"咪唑烷"分子片断有机结合,以水杨醛和乙二胺为起始原料,经缩合、NaBH4还原制得N,N'-二邻羟苄基乙二胺(2),进而与芳醛类化合物缩合关环,合成了8种N,N'-二(2-羟苄基)取代咪唑烷类化合物(3a～3h). 化合物的结构经1H NMR、IR、MS和元素分析等测试技术进行了表征. 结果表明,水杨醛与乙二胺的缩合反应,可专一性地生成对称双缩席夫碱化合物(1);芳醛上的取代基对缩合关环反应有显著影响,邻、对位吸电基可使芳醛的羰基活化,有利于缩合关环反应的进行,邻、对位供电基可使芳醛的羰基钝化,不利于缩合关环反应进行. 抑菌测试结果表明,质量分数为0.1%时,N,N'-二(2-羟苄基)取代咪唑烷化合物对不同菌株的抑菌活性具有明显的特异性,对白色念珠菌、大肠杆菌的抑菌率达100%.

Synthesis, Characterization and Antibacterial Activity of N,N'-Bis(2-hydroxybenzyl) Substituted Imidazolidine Derivatives

A series of N, N'-bis (2-hydroxy benzyl) substituted imidazolidine derivatives (3a ～3h) were designd and synthesized by means of combining segments o-hydroxy phenyl and imidazolidine compounds, according to the reinforcement of biological activities. The N,N'-bis-o-hydroxy benzyl diaminoethane(2) was synthesized using salicylaldehyde and 1,2-diaminoethane, through condensation reaction and then reduction by NaBH_4, and further cyclization with aromatic aldehydes. The structures of all the compounds were confirmed by ~1H NMR, IR, mass spectra and elemental analysis. The results show that the reaction of salicylaldehyde with 1,2-diaminoethane only formed the symmetric Schiff base(1) , the condensation of aromatic aldehyde with compound 2 was noticeably different for different substituents: o-,p-substituted electron-withdrawing groups can activate aromatic aldehyde and result in a higher yield of ring closing reaction, but o- p-substitute electron-donating groups have opposite effects. The result of preliminary bioassay shows that the target compounds had obvious specificity to different bacteria at 0. 1 % (mass concentration) , and had an inhibitory rate of 100% on Monilia albican and Escherichia coli.