以1-肼羰亚甲基-2-三氟甲基苯并[d]咪唑(1)为原料,与芳基异硫氰酸酯在无水乙醇中反应得酰氨基硫脲2a~2d,继而在氢氧化钠水溶液中合环得4,5-二氢-3-(2-三氟甲基苯并[d]咪唑-1-亚甲基)-4-芳基-1,2,4-三唑-5-硫酮(3a~3d),然后分别采用超声辐射法和常规加热法与四种胺反应合成了16个未见报道的Mannich碱4a~4d,5a~5d,6a~6d和7a~7d.与常规加热法对比,超声辐射法具有操作简单,反应时间短,条件温和,产率高,副反应少等优点,为此类化合物的合成提供了一种有效的新方法.目标化合物的结构经元素分析,IR和1H NMR确证.
The reaction of 1-hydrazinocarbonylmethyl-2-trifluoromethylbenzo[d]imidazole (1) with aryl isothiocyanate gave 4-acylthiosemicarbazides 2a~2d in the presence of anhydrous ethanol. Then compounds 2a~2d were cyclized in aqueous sodium hydroxide to afford 4,5-dihydro-3-(2-trifluoromethylbenzo[d]imidazole- 1-ylmethyl)-4-aryl- 1,2,4-triazole-5-thiones (3a~3d). And resulting compounds 3a~3d were treated with four amines to obtain sixteen new Mannich bases 4a~4d, 5a~5d, 6a~6d and 7a~7d by means of ultrasonic radiation method and ordinary method. Compared with ordinary method, ultrasonic radiation method consistently had many merits with simple operation, short time, mild reaction conditions, excellent yields and less secondary reactions, which afforded an effective method to synthesize Mannich base. The structures of the products were confirmed by elemental analysis, IR and ^1H NMR spectra.