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
Pentaerythritol diacetals and diketals from aromatic aldehydes,aliphatic aldehydes,α,β-unsaturated aldehydes and ketones were synthesized using methanesulfonic acid as catalyst in cyclohexane under reflux temperatur...Pentaerythritol diacetals and diketals from aromatic aldehydes,aliphatic aldehydes,α,β-unsaturated aldehydes and ketones were synthesized using methanesulfonic acid as catalyst in cyclohexane under reflux temperature.The products were characterized by IR,1H NMR and elemental analysis.The procedure provided a simplified synthetic method under moderate condition in shorter reaction time,which avoids using corrosive catalyst,harmful organic solvent and water separator during the reaction.展开更多
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Pentaerythritol diacetals and diketals from aromatic aldehydes,aliphatic aldehydes,α,β-unsaturated aldehydes and ketones were synthesized using methanesulfonic acid as catalyst in cyclohexane under reflux temperature.The products were characterized by IR,1H NMR and elemental analysis.The procedure provided a simplified synthetic method under moderate condition in shorter reaction time,which avoids using corrosive catalyst,harmful organic solvent and water separator during the reaction.
