“…Due to remarkable biological and pharmacological activities and versatile use of DHPMs, the synthesis of DHPMs has been revalued. Several improved synthetic methodologies for the Biginelli condensation have recently been developed by employing various catalysts such as p-toluenesulfonic acid [16], Ni(II) coordination complex [17], chloroacetic acid [18], TiCl 4 [19], RuCl 3 [20], Sc(OTf) 3 [21], Co(OAc) 2 [22], sulfated zirconia [23], FeCl 3 .6H 2 O [24], MgBr 2 [25], NbCl 5 [26], Yb(OTf) 3 [27], InCl 3 [28], CuCl 2 [29], SnCl 2 [30], BF 3 .OEt 2 [31], ZrCl 4 [32], ZnCl 2 [33], TMSOTf [34], CdCl 2 [35], CH 3 SO 3 H [36], Iron(III) [37], SmI 2 [38], Pb(NO 3 ) 3 [39], Ba(OH) 3 [40], solvent-free synthesis [41], microwave irradiation [42], ultrasound radiation [43], visible light irradiation [44], Brønsted acidic ionic liquid [45], solid supported reagent [46][47][48][49][50], and enzymatic catalysts [51]. In spite of progress in the synthesis of these compounds, however, some of the previously reported procedures have significant drawbacks such as harsh reaction conditions, low product yield, use of expensive or toxic reagents, laborious workup, and large amount of toxic wastes generation.…”