Ionic liquids catalyzed Biginelli reaction under solvent-free conditions

Magnesium Chloride Hexahydrate Catalyzed One‐Pot Synthesis of 3,4‐Dihydropyrimidin‐2‐(1H)ones Under Solvent‐Free Conditions

“…7H 2 O, [11] Bi(OTf) 3 , [12] KHSO 4 , [13] ionic liquids (BMImPF 6 and BMImBF 4 ), [14] Mn(OAc) 3 . 2H 2 O, [15] or TMSOTf [16] as the catalyst. However, some of the catalysts are expensive, complex or unavailable, and some of these methods require vigorous reactions, prolonged standing and tedious manipulations to isolation the products.…”

Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Catalyzed by Brönsted Acidic Ionic Liquid

“…其传统合成方法是将乙酰乙酸乙酯、芳香醛 和尿素在浓盐酸催化下于乙醇中加热回流得到 3,4-二氢 嘧啶-2-酮衍生物, 存在反应时间长、收率低等缺点. 为 此, 人们不断的寻找新的高效催化剂以改进该类化合物 的合成, 例如以氯化锆 [11] 、溴化铟 [12] 、树脂 [13] 、离子液 体 [14] 、乙酸锰 [15] 、氯化镧 [16] 、硼酸 [17] 、氯化铈 [18] 、三 氟甲烷磺酸镧 [19] 、HBF 4 -SiO 2 [20] 、碘化镓 [21] …”

Cobalt supported on alumina as green catalyst for Biginelli reaction in mild conditions: effect of catalyst preparation method

“…Biginelli multicomponent reaction is a cyclocondensation of aldehyde, β-ketoester, and urea/thiourea under acidic conditions [16]. It is usually performed in an homogeneous system in the presence of acid as HCl [17], H 2 SO 4 [18], NH 2 SO 3 H [19], HBF 4 [20], CCl 3 CO 2 H [21] and ionic liquids as BMImBF 4 [22], [hmim]HSO 4 [23] and [C 3 SO 3 HDoim]HSO 4 [24]. These acids are corrosive, pollutant and unrecoverable.…”