A novel polymeric catalyst for the one-pot synthesis of 2,4,5-triaryl-1H-imidazoles

Magnetic nanoparticle-supported sulfonic acid as a green catalyst for the one-pot synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions

In this work, magnetic nanoparticle-supported sulfonic acid (γ-Fe2O3-SO3H) is used as an efficient catalyst in the synthesis of 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles in a short time (40–70 min for trisubstituted imidazoles and 30–40 min for tetrasubstituted imidazoles) and high-purity products were obtained (92–98% for trisubstituted imidazoles and 94–98% for tetrasubstituted imidazoles) in simple multicomponent reactions. The structure of these products was confirmed via FT-IR and NMR. Green and recyclable catalysts, eco-friendly and solvent-free conditions, high catalytic activity, shorter reaction time, easy recovery by an external magnet, high purity, and excellent yields are some features of these reactions.

Imidazolium-Catalyzed Synthesis of an Imidazolium Catalyst

The chemistry of imidazolium-catalyzed imidazolium synthesis was studied as part of an effort to develop a plausible prebiotic synthesis of a small catalytic molecule capable of catalyzing its own synthesis. Specifically, we investigated the one-pot 1-ethyl-3-methylimidazolium acetate (EMIM-Ac) catalyzed synthesis of 1,3-dibutyl-4,5-difuryl-imidazolium acetate (DBDFIM-Ac) from furfural, n-butylamine, formaldehyde, and acetic acid at 80 °C. Liu et al. (2012) had previously demonstrated the first reaction of the synthetic process, the EMIM-Ac catalyzed benzoin condensation of furfural that yields furoin. Our early studies established the second reaction of the synthetic process, the multicomponent reaction of furoin, n-butylamine, formaldehyde, and acetic acid that yields the imidazolium salt, DBDFIM-Ac. Studies of the complete two-reaction process that uses furfural for the synthesis of DBDFIM-Ac showed that the highest yield of DBDFIM-Ac was obtained when the mole ratio of n-butylamine, formaldehyde, and acetic acid relative to furfural was respectively (0.5:0.25:0.25:1.0-furfural), or one-half of the stoichiometric ratio (1.0:0.5:0.5:1.0-furfural). A time course study of the process showed transient formation of furoin, the obligatory reaction intermediate. DBDFIM-Ac and the imidazolium side product, 1,3-dibutyl-4,5-trifuryl-imidazolium acetate (DBTFIM-Ac), were stable under the reaction conditions. Imidazolium products (DBDFIM and DBTFIM) and the furoin intermediate were not formed in control reactions (80 °C, 24 h) in which EMIM catalyst was either absent or replaced with an equal volume of acetonitrile or DMF. The imidazolium product, DBDFIM-Ac, was shown to catalyze the synthesis of structurally similar 1,3-dipentyl-4,5-difuryl-imidazolium acetate (DPDFIM-Ac) from furfural, n-pentylamine, formaldehyde, and acetic acid at 80 °C.

Direct synthesis of 2,4,5-trisubstituted imidazoles from primary alcohols by diruthenium(ii) catalysts under aerobic conditions

A straightforward synthetic approach to 2,4,5-trisubstituted imidazoles from readily available primary alcohols using arene diruthenium(ii) catalysts has been described.

Isocyanurate-based periodic mesoporous organosilica (PMO-ICS): a highly efficient and recoverable nanocatalyst for the one-pot synthesis of substituted imidazoles and benzimidazoles

Isocyanurate bridging periodic mesoporous organosilica (PMO-ICS) was shown to be a highly active and efficient recyclable nanocatalyst for three-component synthesis of trisubstituted imidazole as well as benzimidazole derivatives in EtOH.

Synthesis and studies of electrochemical properties of lophine derivatives

A versatile series of lophine derivatives (1–13) were synthesized and characterized, Fourier transform infrared spectroscopy (FTIR), Liquid Chromatography-Mass Spectrometry (LC-MS), and ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy.