Recent Advances in the Catalytic Synthesis of Imidazolidin-2-ones and Benzimidazolidin-2-ones

Casnati, Alessandra; Motti, Elena; Mancuso, Raffaella; Gabriele, Bartolo; Cà, Nicola Della

doi:10.3390/catal9010028

“…Cyclic ureas are important intermediates for pharmaceuticals, agricultural chemicals, natural products, chiral auxiliaries, and so on. 1 2-Imidazolidinone is the simplest cyclic urea, and the synthesis from ethylenediamine (EDA) is often used as a model reaction for cyclic urea syntheses. The methods for the synthesis of 2-imidazolidinone are shown in Scheme 1.…”

Section: ■ Introductionmentioning

confidence: 99%

CeO₂-Catalyzed Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

Peng

¹

,

Tamura

²

,

Yabushita

³

et al. 2021

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CeO 2 acted as an effective and reusable heterogeneous catalyst for the direct synthesis of 2-imidazolidinone from ethylenediamine carbamate (EDA-CA) without further addition of CO 2 in the reaction system. 2-Propanol was the best solvent among the solvents tested from the viewpoint of selectivity to 2-imidazolidinone, and the use of an adequate amount of 2-propanol provided high conversion and selectivity for the reaction. This positive effect of 2-propanol on the catalytic reaction can be explained by the solubility of EDA-CA in 2-propanol under the reaction conditions and no formation of solvent-derived byproducts. This catalytic system using the combination of the CeO 2 catalyst and the 2-propanol solvent provided 2-imidazolidinone in up to 83% yield on the EDA-CA basis at 413 K under Ar. The reaction conducted under Ar showed a higher reaction rate than that with pressured CO 2 , which clearly demonstrated the advantage of the catalytic system operated at low CO 2 pressure or even without CO 2 .

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“…[126][127][128][129][130][131] Cyclic and Non-cyclic Urea Derivatives Nitrogen, sulfur and oxygen based nucleophiles can attack "carbamate" carbons to yield (benz)imidazolones,( benzo)thiazolones,( benz)oxazolinones and non-cyclic urea derivatives. [135] Some can even be prepared catalyst-free at 180 8 8C and 100 bar of CO 2 . [136] However,a nilines,s econdary amines and amines of low basicity do not react in the absence of ac atalyst.…”

Section: Methodsmentioning

confidence: 99%

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO₂

Hulla

¹

,

Dyson

²

2019

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Organocatalysts promote a range of C−N bond forming reactions of amines with CO2. Herein, we review these reactions and attempt to identify the unifying features of the catalysts that allows them to promote a multitude of seemingly unrelated reactions. Analysis of the literature shows that these reactions predominantly proceed by carbamate salt formation in the form [BaseH][RR′NCOO]. The anion of the carbamate salt acts as a nucleophile in hydrosilane reductions of CO2, internal cyclization reactions or after dehydration as an electrophile in the synthesis of urea derivatives. The reactions are enhanced by polar aprotic solvents and can be either promoted or hindered by H‐bonding interactions. The predominant role of all types of organic and salt catalysts (including ionic liquids, ILs) is the stabilization of the carbamate salt, mostly by acting as a base. Catalytic enhancement depends on the combination of the amine, the base strength, the solvent, steric factors, ion pairing and H‐bonding. A linear relationship between the base strength and the reaction yield has been demonstrated with IL catalysts in the synthesis of formamides and quinazoline‐2,4‐diones. The role of organocatalysts in the reactions indicates that all bases of sufficient strength should be able to catalyze the reactions. However, a physical limit to the extent of a purely base catalyzed reaction mechanism should exist, which needs to be identified, understood and overcome by synergistic or alternative methods.

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“…Nitrogen, sulfur and oxygen based nucleophiles can attack “carbamate” carbons to yield (benz)imidazolones, (benzo)thiazolones, (benz)oxazolinones and non‐cyclic urea derivatives . Some can even be prepared catalyst‐free at 180 °C and 100 bar of CO 2 .…”

Section: Cyclic and Non‐cyclic Urea Derivativesmentioning

confidence: 99%

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO₂

Hulla

¹

,

Dyson

²

2019

View full text Add to dashboard Cite

Organocatalysts promote a range of C−N bond forming reactions of amines with CO2. Herein, we review these reactions and attempt to identify the unifying features of the catalysts that allows them to promote a multitude of seemingly unrelated reactions. Analysis of the literature shows that these reactions predominantly proceed by carbamate salt formation in the form [BaseH][RR′NCOO]. The anion of the carbamate salt acts as a nucleophile in hydrosilane reductions of CO2, internal cyclization reactions or after dehydration as an electrophile in the synthesis of urea derivatives. The reactions are enhanced by polar aprotic solvents and can be either promoted or hindered by H‐bonding interactions. The predominant role of all types of organic and salt catalysts (including ionic liquids, ILs) is the stabilization of the carbamate salt, mostly by acting as a base. Catalytic enhancement depends on the combination of the amine, the base strength, the solvent, steric factors, ion pairing and H‐bonding. A linear relationship between the base strength and the reaction yield has been demonstrated with IL catalysts in the synthesis of formamides and quinazoline‐2,4‐diones. The role of organocatalysts in the reactions indicates that all bases of sufficient strength should be able to catalyze the reactions. However, a physical limit to the extent of a purely base catalyzed reaction mechanism should exist, which needs to be identified, understood and overcome by synergistic or alternative methods.

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Recent Advances in the Catalytic Synthesis of Imidazolidin-2-ones and Benzimidazolidin-2-ones

Cited by 26 publications

References 190 publications

CeO₂-Catalyzed Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

CeO₂-Catalyzed Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO₂

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO₂

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Recent Advances in the Catalytic Synthesis of Imidazolidin-2-ones and Benzimidazolidin-2-ones

Cited by 26 publications

References 190 publications

CeO2-Catalyzed Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

CeO2-Catalyzed Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO2

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO2

Contact Info

Product

Resources

About

CeO₂-Catalyzed Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

CeO₂-Catalyzed Synthesis of 2-Imidazolidinone from Ethylenediamine Carbamate

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO₂

Pivotal Role of the Basic Character of Organic and Salt Catalysts in C−N Bond Forming Reactions of Amines with CO₂