Ionic liquid promoted synthesis of heterocycle-fused pyrimidine-2,4(1H,3H)-diones utilising CO2

Li, Chun; Lu, Xunhua; Yang, Yuanyong; Yang, Sheng-Gang; Zhang, Lin

doi:10.1016/j.tetlet.2018.05.043

Cited by 12 publications

(4 citation statements)

References 31 publications

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“…fused pyrimidine-2,4(1H,3H)-diones in moderate to high yields. 19 2.1.2. Cyclization of Propargylic Alcohols with CO 2 .…”

Section: Ionic-liquid-catalyzed Strategies For the Transformation Of ...mentioning

confidence: 99%

“…Azolate-based ILs such as [Bu 4 P][2-MIm], [Bu 4 P][3-MIm], [Bu 4 P][4-MIm], and [Bu 4 P][Im] could also catalyze this reaction; however, they required higher temperature (e.g., 80 °C) and had lower activity compared to [HDBU][TFE] . Zhang and co-workers synthesized a protic IL, [HDBN][TFE], and applied it in catalyzing the reaction of aromatic heterocyclic o -amino nitriles with atmospheric CO 2 , producing heterocycle-fused pyrimidine-2,4(1 H ,3 H )-diones in moderate to high yields …”

Section: Ionic-liquid-catalyzed Strategies For the Transformation Of ...mentioning

confidence: 99%

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Ionic-Liquid-Catalyzed Approaches under Metal-Free Conditions

2021

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Conspectus Metal-free catalysis is a promising protocol to access chemicals without metal contamination. Ionic liquids (ILs) that are entirely composed of organic cations and inorganic/organic anions have emerged as promising alternatives to molecular solvents and metal catalysts due to their unique properties such as structural tunability, the coexistence of multiple interactions among ions (e.g., electrostatic interaction, hydrogen bonding, van de Waals forces, acid/base interactions, hydrophilic/hydrophobic interactions, etc.), unique affinity for a wide range of chemicals, good chemical and thermal stability, and quite low volatility. ILs have shown potential applications in various chemical processes. In this Account, we systematically described our most recent work on IL-catalyzed approaches under metal-free conditions. The first section presents the IL-catalyzed strategies toward the transformation of CO2 to value-added chemicals, focusing on the CO2-reactive IL-catalyzed CO2 transformation to various heterocycles and the IL-catalyzed reductive transformation of CO2 to chemicals. In these approaches, we designed task-specific ILs that are able to chemically capture and activate CO2 via forming anion-based carbonate/carbamate or cation-based carboxylate/carbamate intermediates, thus further accomplishing its transformation to a series of heterocycles including quinazoline-2,4(1H,3H)-diones, cyclic carbonates, 2-oxazolidinones, oxazolones, and benzimidazolones under metal-free conditions. For the IL-catalyzed approaches to reducing CO2 with hydrosilanes to chemicals, we employed ILs capable of activating the Si–H bond in hydrosilanes and the N–H bond in amine substrates via H-bonding, thus achieving the reductive transformation of CO2 to formamides, benzimidazoles, and benzothiazoles via cooperative catalysis. The second section describes our finding on the IL-catalyzed hydration of the CC bond in propargylic alcohols. Azolate anion-based ILs that can chemically capture CO2 via the formation of carbamates could serve as robust nucleophiles to attack the CC bond in propargylic alcohols and then efficiently catalyze the hydration of propargylic alcohols to produce α-hydroxy ketones with the assistance of atmospheric CO2 gas under metal-free conditions. The third section unveils the cooperative catalysis strategy of hydrogen bond donors and acceptors of ILs for chemical reactions. In the hydrogen-bonding catalysis protocols, cations of the ILs act as H-bond donors and anions, as acceptors, forming H-bonds with the reactant molecules, respectively, in opposite ways, which can cooperatively catalyze the ring-closing C–O/C–O bond metathesis reactions of aliphatic diethers to O-heterocycles, the dehydrative etherification of alcohols to ethers, and direct oxidative esterification of alcohols to esters. We believe that these IL-catalyzed metal-free processes and strategies display promising practical applications, and their commercialization would bring great benefits to the production of the as-afforded value-...

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“…fused pyrimidine-2,4(1H,3H)-diones in moderate to high yields. 19 2.1.2. Cyclization of Propargylic Alcohols with CO 2 .…”

Section: Ionic-liquid-catalyzed Strategies For the Transformation Of ...mentioning

confidence: 99%

Section: Ionic-liquid-catalyzed Strategies For the Transformation Of ...mentioning

confidence: 99%

Ionic-Liquid-Catalyzed Approaches under Metal-Free Conditions

2021

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“…Fujita reported just an example of pyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione (footnote to entry 1, Table 5) [160], but almost at the same time Zhang and co-workers published a detailed study on the synthesis of many dihydropyrimidine-2,4(1H,3H)-diones fused with heterocycles (Scheme 29) [193].…”

Section: Cyclic Ureasmentioning

confidence: 99%

“…Since the carboxylation of amines by CO 2 is known to proceed with almost no activation barrier, the role of imidazolidin-2-one cannot favor an increase of the nucleophilicity of the diamine, but rather to assist the catalyst in the protonation and deprotonation steps of the catalytic cycle, very likely via its enolic form. the synthesis of many dihydropyrimidine-2,4(1H,3H)-diones fused with heterocycles (Scheme 29) [193]. Also the solvent play an important role, because it should be polar enough to stabilize anionic species, but it must not interact strongly with the base catalyst via hydrogen bonding.…”

Section: Cyclic Ureasmentioning

confidence: 99%

Recent Advances in the Chemical Fixation of Carbon Dioxide: A Green Route to Carbonylated Heterocycle Synthesis

et al. 2019

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Carbon dioxide produced by human activities is one of the main contributions responsible for the greenhouse effect, which is modifying the Earth’s climate. Therefore, post-combustion CO2 capture and its conversion into high value-added chemicals are integral parts of today’s green industry. On the other hand, carbon dioxide is a ubiquitous, cheap, abundant, non-toxic, non-flammable and renewable C1 source. Among CO2 usages, this review aims to summarize and discuss the advances in the reaction of CO2, in the synthesis of cyclic carbonates, carbamates, and ureas appeared in the literature since 2017.

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