Environmentally benign and diastereoselective synthesis of 2,4,5-trisubstituted-2-imidazolines

Phuong, Hai Anh Le; Cseri, Levente; Whitehead, George F. S.; Garforth, Arthur; Budd, Peter M.; Székely, György

doi:10.1039/c7ra11827a

Cited by 11 publications

(10 citation statements)

References 35 publications

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“…For example, Hunt and co-workersf ound that the synthesis of b-sitosterol throught he biocatalytic reaction of b-sitosterol and fattya cids did not proceed when Cyrene was used as the solvent. [60] Instead of the desired product, ac omplex reaction mixture was obtained, which was presumably the result of the reactionoft he solvent with the reagents. It is unclear from theses tudies if Cyrenei sa na ctive substrate for the enzymes or if there are other problemsf or biocatalytic processes( see below).…”

Section: Use Of Cyrene As Abio-available Solventmentioning

confidence: 99%

“…[59] As expected, Cyrene was also not ag ood solventf or the preparation of 2,4,5-trisubstituted-2-imidazolines 47 from the condensation reactiono fa ldehydes,s uch as 4-(trifluoromethyl)benzaldehyde (46), and ammonium carbonate (Scheme 12). [60] Instead of the desired product, ac omplex reaction mixture was obtained, which was presumably the result of the reactionoft he solvent with the reagents.…”

Section: Use Of Cyrene As Abio-available Solventmentioning

confidence: 99%

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Bio‐available Solvent Cyrene: Synthesis, Derivatization, and Applications

2018

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The development of green solvents is one of the key tenets of Green Chemistry as solvents account for the majority of waste stemming from the production of the chemicals on which we have all come to rely. An important class of solvents is the dipolar aprotics, which include N,N-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP). In addition to being derived from non-renewable resources, these solvents are also under increased regulatory pressures that will limit their industrial applications. This Concept concerns the bio-available solvent Cyrene (dihydrolevoglucosenone) as a potential replacement for toxic dipolar aprotic solvents. An emphasis is placed on examining the strengths and weaknesses of Cyrene as a solvent and is accomplished by looking at the synthesis, derivatization, and application in synthetic protocols of Cyrene. With respect to the Twelve Principles of Green Chemistry, this Concept describes a bio-available solvent that should have a disruptive effect on the use of traditional industrial dipolar aprotic solvents.

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Section: Use Of Cyrene As Abio-available Solventmentioning

confidence: 99%

Section: Use Of Cyrene As Abio-available Solventmentioning

confidence: 99%

Bio‐available Solvent Cyrene: Synthesis, Derivatization, and Applications

2018

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“…The product could not be crystallised, it could only be obtained in low yields after subsequent extraction and preparative HPLC purification steps. The instability of Cyrene in basic media, 34 and the use of PC as an alkylating agent for phenols have been reported. 35 Solvent recovery experiments were performed to study the feasibility of recycling of 1C after the reaction.…”

Section: Extending the Application Of Polarcleanmentioning

confidence: 99%

Towards cleaner PolarClean: efficient synthesis and extended applications of the polar aprotic solvent methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate

Cseri

Székely

2019

Green Chem.

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“…OSN is a predictable and energy-efficient technology compared to other separation techniques such as distillation, chromatography, and extraction [32]. There is an increasing interest in applying OSN for the purification of pharmaceutically relevant compounds [33][34][35][36], as well as solvent recovery [37,38]. OSN has also been proposed for the recovery of enlarged metal catalysts [39], and organocatalysts [40].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of C3-Symmetric Cinchona-Based Organocatalysts and Their Application in Asymmetric Michael and Friedel–Crafts Reactions

Kisszékelyi¹,

Fehér²,

Nagy³

et al. 2021

Preprint

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In this work, anchoring of cinchona derivatives to trifunctional cores (hub approach) was demonstrated to obtain size-enlarged organocatalysts. By modifying the cinchona skeleton in different positions, we prepared four C3-symmetric size-enlarged cinchona derivatives (hub-cinchonas), which were tested as organocatalysts and their catalytic activities were compared with the parent cinchona (hydroquinine) catalyst. We showed that in the hydroxyalkylation reaction of indole, hydroquinine provides good enantioselectivities (up to 73% ee), while the four new size-enlarged derivatives gave significantly lower values (up to 29% ee) in this reaction. Anchoring cinchonas to trifunctional cores was found to facilitate nanofiltration-supported catalyst recovery using PolarClean alternative solvent. The C3-symmetric size-enlarged organocatalysts were completely rejected by all the applied membranes, whereas the separation of hydroquinine was found to be insufficient using organic solvent nanofiltration. Furthermore, the asymmetric catalysis was successfully demonstrated in the case of Michael reaction of 1,3-diketones and trans-β-nitrostyrene using Hub3-cinchona (up to 96% ee) as a result of the positive effect of the C3-symmetric structure using a bulkier substrate. This means an increased selectivity of the catalyst in comparison to hydroquinine in the latter Michael reaction.

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Environmentally benign and diastereoselective synthesis of 2,4,5-trisubstituted-2-imidazolines

Abstract: A one-pot, membrane-assisted synthesis of 2,4,5-trisubstituted-2-imidazolines was developed, and substituent effects, reaction kinetics and mechanism by DFT were studied.

Cited by 11 publications

References 35 publications

Bio‐available Solvent Cyrene: Synthesis, Derivatization, and Applications

Bio‐available Solvent Cyrene: Synthesis, Derivatization, and Applications

Towards cleaner PolarClean: efficient synthesis and extended applications of the polar aprotic solvent methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate

Synthesis of C3-Symmetric Cinchona-Based Organocatalysts and Their Application in Asymmetric Michael and Friedel–Crafts Reactions

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