Efficient Catalytic Synthesis of 3,4‐Dihydropyrimidin‐2‐ones/thiones via Little Acidic Ionic Liquid Combined with Rapid Heating Ways

Abstract

in Wiley Online Library (wileyonlinelibrary.com).Catalytic synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones was efficiently promoted by as little as 2.5 mol% of Brønsted acidic ionic liquid [(CH 2 ) 3 SO 3 HMIM]HSO 4 catalyst loading via rapid heating ways. Interestingly, rapid heating effectively improved yields to avoid side products. Furthermore, the mechanism has been speculated that the reaction proceeds may be via rapidly one-step condensation rather than slowly step-by-step condensation. In addition, the catalyst can be recovered for repeated use (up to seven times), and a whole green reaction process adds to its practical applicability.

Sulfonic Acid and Ionic Liquid Functionalized Covalent Organic Framework for Efficient Catalysis of the Biginelli Reaction

“…By comparison, sulfonic acid-functionalized ionic liquids containing the HSO 4 – counteranion would enhance the Brønsted acidity of the catalyst (Table S2), which is well consistent with the previous work . Of note, COF-IM-SO 3 H herein is one of the best catalysts for the Biginelli reaction among the reported heterogeneous catalysts (Table S3), − which may be attributed to its high density of sulfonic acid moiety and high surface area.…”

Polymer/ZIF‐67 composite as an effective and recyclable nanocatalyst for Biginelli reaction

“…PAA/ZIF-67 exhibits benefits in terms of cost-effectiveness, reaction time, simplicity, yield, solvent, and temperature. Anionic Zn (II)-MOF 10 wt% 2 h -60 93 [53] PTA@MIL-101 0.006 mmol 1 h -100 90 [54] Cu-based MOF 0.1 mmol 2 h -60 86 [55] ompg-C 3 N 4 /SO 3 H 30 mg 30 min EtOH reflux 94 [56] BIL-SO 3 H 2.5 mol % 3 h EtOH 80 98 [57] COF-IM-SO 3 H 8.64 mg (1.0 mol%) 2.5 h -90 98 [15] Ni-DDIA 0.005 mmol 30 min -80 84.6 [16] 0.2NbCl 5 -BMImCl 5 mol% 30 min -100 90 [17] PAA/ZIF-67 15 mg 30 min -75 94 This work PAA/ZIF-67 nanocomposite was fabricated by growing ZIF-67 onto the surface of PAA and applied as a recoverable catalyst for the one-pot synthesis of dihydropyrimidinone derivatives via the condensation of various aldehydes, urea, and ethyl acetoacetate under solventfree conditions. This composite demonstrated a combination of fascinating features, including high surface area, stability, and redispersing capability.…”