A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified on...A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.展开更多
3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of aldehyde,1,3-dicarbonyl compound,and urea or thiourea using copper o-toluenesulfonate as a catalyst under solvent-free...3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of aldehyde,1,3-dicarbonyl compound,and urea or thiourea using copper o-toluenesulfonate as a catalyst under solvent-free conditions at 90℃.Effects of molar ratio of reactants,amount of catalyst,and reaction temperature on the yields of 3,4-dihydropyrimidin-2-(1H)-ones were investigated.The results showed that at the condition of naldehyde∶n1,3-dicarbonyl compounds∶nurea(or thiourea)=1∶1.2∶1.5,1 mol% catalyst(molar percent of aldehyde),2.0 h at 90℃,the yields of products were 51-96%.After reaction,the catalyst could be reused for four times without distinct loss of catalytic activity.展开更多
文摘A novel catalyst indium(Ⅲ) tribromide is shown to efficiently promote 5-carbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones from a three-component coupling of β-diketones, aldehydes and urea in ethanol. This modified one-pot Biginelli′s cyclocondensation not only features simple operation, but also takes place in nonpolluted environment. The structure of the Biginelli reaction product from β-diketones, salicylaldehyde and urea has been proposed to possess an oxygen-bridge.
文摘3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of aldehyde,1,3-dicarbonyl compound,and urea or thiourea using copper o-toluenesulfonate as a catalyst under solvent-free conditions at 90℃.Effects of molar ratio of reactants,amount of catalyst,and reaction temperature on the yields of 3,4-dihydropyrimidin-2-(1H)-ones were investigated.The results showed that at the condition of naldehyde∶n1,3-dicarbonyl compounds∶nurea(or thiourea)=1∶1.2∶1.5,1 mol% catalyst(molar percent of aldehyde),2.0 h at 90℃,the yields of products were 51-96%.After reaction,the catalyst could be reused for four times without distinct loss of catalytic activity.
文摘80℃、无溶剂条件下,以四氯化锡为催化剂,芳香醛、β-酮酯、N-取代的(硫)脲三组分通过Biginelli缩合反应合成了一系列N1-取代的-4-芳基-3,4-二氢嘧啶-2(1H)-(硫)酮。反应在较短的时间(0.2-6.0 h)内获得了较好的收率(46-94%)。底物适用范围广是该工艺的一个显著优势。产品结构通过IR,1H NMR,13 C NMR和元素分析方法进行了表征。目标化合物的晶体结构通过X-射线单晶衍射进行了确证。
