A sequential one-pot approach to 1,2,4,5-tetrasubstituted-2H-imidazole synthesis from disubstituted alkynes

Abstract

A sequential one-pot approach to the tetrasubstituted 2H-imidazole scaffolds has been developed from disubstituted alkynes and structurally diverse ketones. The reaction proceeds via a diketo intermediate generated from internal alkynes followed by the addition of ammonium acetate and a suitable ketone, affording a diverse range of 2H-imidazoles. Using air-moisture stable reaction conditions and inexpensive reagents, the transformation demonstrates a broad substrate scope and good functional group compatibility.Scheme 1 Our previous and present studies.

An iodine/DMSO-catalyzed sequential one-pot approach to 2,4,5-trisubstituted-1H-imidazoles from α-methylene ketones

“…Accordingly, the oxidation of B is not solely a DMSO catalyzed reaction, since the catalytic water still exists, but majorly relies on the DMSO to react with the α-iodinated intermediate to afford the diketone intermediate 5. In terms of the coupling reaction, 33 iodine is capable of binding to the carbonyl oxygen of the diketone intermediate 5 and aldehyde 2, owing to its mild Lewis acidity, thus increasing the reactivity of the substrates, 34 which is supported by control experiment 7b. Moreover, iodine facilitates the formation of the imine intermediates H and I which condense to form the desired imidazole 3.…”

“…In terms of the coupling reaction, 33 iodine is capable of binding to the carbonyl oxygen of the diketone intermediate 5 and aldehyde 2, owing to its mild Lewis acidity, thus increasing the reactivity of the substrates, 34 which is supported by control experiment 7b. Moreover, iodine facilitates the formation of the imine intermediates H and I which condense to form the desired imidazole 3.…”

A Breakthrough in Solution‐Processed Ultra‐Deep‐Blue HLCT OLEDs: A Record External Quantum Efficiency Exceeding 10% Based on Novel V‐Shaped Emitters

“…The intermediate 4ʹ,5ʹ-bis(4-bromophenyl)spiro[ fluorene-9,2ʹ-imidazole] (FIP-Br) was synthesized by Debus-Radziszewski imidazole synthesis with a yield of 58.9%. [20] The final compounds FIP-CZ, FIP-tBuCZ, FIP-DPA, and FIP-tBuDPA were obtained by palladium-catalyzed Buchwald-Hartwig amination reaction with yields of 94.5%, 89.9%, 93.4%, and 86.2%, respectively. [21] The…”

Ionic Liquid Solvation versus Catalysis: Computational Insight from a Multisubstituted Imidazole Synthesis in [Et2NH2][HSO4]

“…The one-pot synthesis of substituted imidazoles is also as uitable example, representing more general nucleophilic addition and cyclocondensation reactions. [14] Moreover,m ulticomponent imidazoles are important structural motifs for antimycobacterial agents in the treatment of tuberculosis, [15] in peptidomimetics design, [16] as antifungal agents, [17] and they are also found in DNA. [18] Imidazole scaffolds are also utilized as anticancer agents, [19] corrosion inhibitors [20] and catholytes forh ybrid Li-air batteries.…”