Novel Non‐toxic and Non‐hazardous Solvent Systems for the Chemistry of Indoles: Use of a Sulfone‐containing Brønsted Acid Ionic Liquid Catalyst in Butyl Acetate

El‐Harairy, Ahmed; Yiliqi,; Yue, Mei-E; Fan, Wenbing; Popowycz, Florence; Queneau, Yves; Li, Minghao; Gu, Yanlong

doi:10.1002/cctc.201900784

Cited by 28 publications

(9 citation statements)

References 101 publications

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“…Ionic liquids are generally inexpensive and readily available 29,30 . The use of ionic liquids instead of strong acids as catalysts for Michael addition is beneficial from both synthetic and environmental points of view.…”

Section: Synthesis Of Raspberry Ketonementioning

confidence: 99%

Advances in the synthesis and applications of raspberry ketone: A review

Guo

Chang

Jia

et al. 2021

Flavour & Fragrance J

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Recent advances in the synthesis and applications of raspberry ketone are reviewed in this paper. Different routes to this material including chemical and biotechnological synthetic methods and extraction from natural sources are compared, and the applications of the ketone in flavour and fragrance, pharmaceuticals and in food and tobacco processing are discussed. Synthesis from petrochemical raw materials has the advantages of ready availability of ingredients and well‐understood synthetic steps, but direct synthesis from petrochemicals will eventually be replaced because of low yields and hazardous results to environment. The ketone can be made from natural raw materials, and the methods are promising if their disadvantages such as limited availability and complex, multi‐step reactions and harsh reaction conditions can be overcome. Biotechnological preparation methods have the advantages of reaction specificity, mild reaction conditions, but are limited in applicability because of complications associated with their synthetic and purification procedures at present. With the development of biotechnology, biotechnological preparation methods of the ketone may be the most important route in the future. Direct extraction of the ketone from natural raw materials is possible, but the cost is very high. From the view of syntheses and applications, the research perspectives of raspberry ketone are outlined in the end of this paper, which are the development of green and effective synthetic methods for raspberry ketone from natural raw materials and the preparation and application of raspberry ketone by biotechnological preparation methods.

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Section: Synthesis Of Raspberry Ketonementioning

confidence: 99%

Advances in the synthesis and applications of raspberry ketone: A review

Guo

Chang

Jia

et al. 2021

Flavour & Fragrance J

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“…Then, the recovery and recycling experiments of ionic liquids as catalysts have been extensively explored, showing broad application prospects. − Meanwhile, simple alcohols are used as reducing agents to effectively participate in the reduction of various functional groups, − which avoids the formation of stoichiometric metallic salts. , The use of green solvents is a crucial factor in reducing environmental impact during the chemical transformation. DMC is classified as a green polar aprotic solvent due to its rich advantages such as rapid biodegradation, low toxicity, and good environmental compatibility, , it has been widely used as the solvent in many reactions. − Moreover, Gu et al proved that a polar aprotic solvent could stabilize the reaction intermediates and improve the reactivities in certain reactions. , …”

Section: Introductionmentioning

confidence: 99%

Acidic Ionic Liquids as Metal-Free and Recyclable Catalysts for Direct Reduction of Aromatic Allylic Alcohol in Dimethyl Carbonate via Hydrogen Transfer

Liu

Han

Zhuang

et al. 2022

ACS Sustainable Chem. Eng.

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Direct reduction of alcohols, to avoid tedious reaction steps, has drawn broad attention. However, the transformation was mainly catalyzed by transition metals or Lewis acids. Developing a metal-free and recyclable catalytic system is still a challenging task from the viewpoint of green chemistry. Herein, pyrrolidine-based ionic liquids as metal-free and recyclable catalysts for direct reduction of aromatic allylic alcohol were developed using p-methylbenzyl alcohol as the reducing agent in dimethyl carbonate (DMC). DMC not only acted as the green solvent but also could stabilize the reaction intermediates and improve the reactivities. Aromatic allylic alcohols with electron-donating or -withdrawing groups could provide up to 92% yield. The gram-scale experiment was performed smoothly, and the recycle experiment of the ionic liquids could be achieved through simple steps, which was significant for environmental protection and efficient utilization of resources. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy proved that ionic liquids interacted with the substrates and the reducing agent by forming multiple hydrogen bonding interactions. Kinetic isotope effect (KIE) experiments (k H /k D = 2.27) indicated that the C−H bond cleavage might be a rate-determining step, and deuterium-labeled results demonstrated that the hydrogen of the product was derived from the benzylic H of p-methylbenzyl alcohol. Meanwhile, the experiments of two preprepared ether intermediates as the substrates showed that they may be involved during the reaction, and a possible mechanism containing intermediates, hydrogen transfer, and hydrogen bonding effects was proposed.

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“…1 Multicomponent reactions (MCRs) have emerged as valuable tools for the development of diverse heterocyclic scaffolds. [2][3][4][5][6][7][8][9][10][11][12] Pyrazolo [3,4-b] quinolinones are also a product of multicomponent synthesis and show important biological properties. They are GSK3 inhibitors, 13 tubulin inhibitors, 14 phosphoinositide 3-kinase inhibitors 15 and potassium channel openers.…”

Section: Introductionmentioning

confidence: 99%