DABCO-catalyzed Knoevenagel condensation of aldehydes with ethyl cyanoacetate using hydroxy ionic liquid as a promoter

Abstract

N-(2-Hydroxy-ethyl)-pyridinium chloride ([HyEtPy]Cl) was synthesized and explored as a novel promoter for 1,4-diazabicyclo [2.2.2] octane (DABCO)-catalyzed Knoevenagel condensation reactions, excellent catalytic activity was obtained.

New dicationic DABCO-based ionic liquids: a scalable metal-free one-pot synthesis of bis-2-amino-5-arylidenethiazol-4-ones

“…Subsequently, the important role of the ILs hydroxyl group in stimulating the carbonyl groups of both rhodanine and aldehydes was also studied to have a better understanding of the catalytic system under investigation [23,38]. To do this, [DABCO-H][OAc] (DIL) 4 was synthesized [28,38] (scheme 1) and employed for catalysing the model reaction (scheme 2) instead of bis-DILs 3a , b .…”

“…This cage-like structure makes the nitrogen lone pair precisely localized, and consequently, DABCO becomes more attuned for quaternization. Accordingly, this merit has been used for the assembly of several types of DABCO-based ILs [23–27]. Latterly, two new ILs based on DABCO were prepared by our group (figure 1) and used successfully as catalysts in the Claisen–Schmidt condensation [28] and multisubstituted imidazoles synthesis [29].…”

Preparation of a novel Fe3O4@SiO2@propyl@DBU magnetic core–shell nanocatalyst for Knoevenagel reaction in aqueous medium

“…DBU, an organic base with steric hindrance, can efficiently catalyze the Knoevenegal reaction, but the reuse and separation of DBU is difficult (43). To address the above questions and to continue our research interests (44,45), a green and efficient Knoevenegal reaction catalyst, Fe 3 O 4 @SiO 2 modified by DBU (Scheme 1), was developed and used in the Knoevenegal reaction, the high reaction yield and short reaction times were obtained. Since the catalyst itself was supported by magnetic Fe 3 O 4 , it is easy to be separated and retains its original activity after 10 times of cyclic tests.…”

Synthesis and styrene copolymerization of halogen novel ring-substituted isobutyl phenylcyanoacrylates

“…Cyanoacrylates is family of vinyl monomers renowned for their high reactivity, instant adhesive properties, and wide-ranging applications [1][2][3]. Trisubstituted ethylenes (TSE), ring-functionalized (R 1 ) alkyl (R 2 ) phenylcyanoacrylates, R 1 PhCH = C(CN)CO2R 2 (PCA) continue to attract attention as compounds with variety of applications [4][5][6][7][8][9][10][11]. Thus, methoxy ring-substituted methyl phenylcyanoacrylate, MPCA was used in synthesis of pyridotriazines and triazolopyridines [4].…”