Synthesis of polyhydroquinolines via Hantzsch’s multicomponent reaction (MCR) involves the use of a hygroscopic and moderately toxic ammonium salt as one of the key reactants. In our effort, we have found urea as an effective ammonia surrogate when the MCR was performed in the presence of sulphonic acid-functionalized Wang resin (Wang-OSO<sub>3</sub>H) as a polymeric and recoverable acidic catalyst under green conditions. Urea is relatively less hygroscopic/toxic than the commonly used ammonium salts used in this MCR. The methodology afforded a range of polyhydroquinolines in good yields. Depending on the nature of reaction conditions employed, the MCR afforded Biginelli product or 1,4-DHPs when the use of 1,3-diketone was omitted.
通过汉奇多组分反应(MCR)合成聚氢喹啉,涉及使用一种吸湿性和中等毒性的铵盐作为关键反应物之一。在我们的努力中,我们发现尿素在存在磺酸基功能化王树脂(Wang-OSO3H)作为聚合物和可回收的酸性催化剂的条件下,作为有效的氨替代品。尿素比这种MCR中常用的铵盐相对更不易吸湿/有毒。该工艺提供了一系列高产率的聚氢喹啉。根据所用反应条件的性质,当省略使用1,3-二酮时,MCR会生成Biginelli产物或1,4-DHPs。