Eco-friendly synthesis of 2,3-dihydroquinazolin-4(1H)-ones in ionic liquids or ionic liquid–water without additional catalyst

Abstract

2,3-Dihydroquinazolin-4(1H)-ones have been synthesized in high to excellent yields through direct cyclocondensation of anthranilamides and aldehydes in ionic liquids (ILs) or one-pot three-component cyclocondensation of isatoic anhydrides, ammonium acetate and aldehydes in ionic liquid-water solvent system without the use of any additional catalyst.

Kinetic Study of Michael Addition Catalyzed by N‐Methylimidazole in Ionic Liquids: Residual N‐Methylimidazole in Ionic Liquids as a Strong Base

“…It is probably due to a less organized structure of pyridinium ILs in comparison to imidazolium ILs. [16,17] Michael addition of 2 to 1 in [empyr]SO 4 Et with 5 mol-% of pyridine as catalyst proceeded with a rate constant of 0.26 ϫ 10 -4 s -1 (Table 1, Entry 21).…”

“…Therefore, we wondered what would be the reaction rate for the addition of 2 to 1 in some binary mixtures of imidazolium-based ILs. The results are collected in 4 Et anion can, in the presence of traces amount of water, hydrolyze to the HSO 4 anion, which can protonate the residual N-methylimidazole. Our observations are in accordance with the results of D'Anna [22] that the effect of binary mixtures [bmim]X/cosolvent on the reaction course cannot be ascribable to simple polarity, viscosity, or conductivity effects, but a whole set of parameters has to be considered.…”

“…In contrast, no product was formed in THF in the Pd-catalyzed α-allylation of 2-phenylpropanal with allyl ethyl carbonate run in IL without any additional basic catalyst. [2] Nucleophilic aromatic substitutions [3] and synthesis of quinazoline derivatives [4] are other examples of reactions that proceeded well in ILs without additional catalysts, but Michael addition reactions of carbonyl compounds to (E)-β-nitrostyrene catalyzed by N-toluensulfonyl--proline amide in acidic ILs did not proceed. [5] The key step in the synthesis of most ILs is alkylation of N-methylimidazole with the corresponding 1-haloalkane.…”

One‐pot synthesis of 2,3‐disubstituted‐2,3‐dihydroquinazolin‐4(1H)‐ones using [Hmim][NO3]: An eco‐friendly protocol

“…Although there are several reports on the synthesis 2,3-disubstuted-2,3-dihydroquinazoline-4(1H)-one derivatives, [14,15] yet the investigations for a convenient and green synthesis is on due to different drawbacks in the existing methods, e.g., harsh reaction conditions, using toxic solvents and metal-based catalysts, low yield, time consuming, and no easy available precursors. Chen et al [16] has reported a new method for the preparation of 2,3-dihydroquinazoline-4(1H)-ones using classic ionic liquids such as [ À anions toward hydrolysis in contact with moisture, forming HF and POF 3 , which can dissolve glassware and damage steel autoclaves and reactors [17].…”

Efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones using heterogeneous solid acid catalysts: unexpected formation of 2,3-dihydro-2-(4-(tetrahydro-2H-pyran-2-yloxy)butyl)-quinazolin-4(1H)-one

“…[1][2][3] Due to their promising biological potential and wide occurrence in nature, several efforts have been made to develop an elegant approach for their synthesis. These include condensation of anthranilamide with aldehydes in presence of acid catalysts 4,5 reductive cyclization of Onitrobenzamide or O-azido-benzamide with aldehydes and ketones using SmI 2 , 6 or using TiCl 4 , 7, 8 reductive desulfurization of 2-thioxo-3H-quinazolin-4-ones with nickel boride in dry methanol, 9 one-pot conversion from 2-nitro-N-arylbenzamides using SnCl 2 , 10 one-pot synthesis using pTSA, 11 silica-SO 3 H, 12 alum, 13 montmorillonite K-10, 14 ionic liquids, 15 and gallium(III) triflate, 16 and enantioselective synthesis using chiral auxillary 3 and Bronsted acid catalyst. 17 Of these, the condensation of anthranilamide with aldehyde or ketone is one of the simplest and …”