Aqueous extracts of biomass ash as an alternative class of Green Solvents for organic transformations: A review update

This work presents a new catalytic application of 4,4′-trimethylenedipiperidine for the efficient synthesis of a series of dihydro-[1,2,4] triazolo[1,5-a]pyrimidines. According to the principles of green chemistry, the reaction was performed (a) in a solvent mixture comprised of water and ethanol (1:1 v/v) at reflux temperature and (b) solvent-free grinding in a mortar by a pestle. The organocatalyst could be reused up to 10 runs, and no reduction of catalytic activity was detected. A variety of substituted dihydro-[1,2,4] triazolo[1,5-a]pyrimidines were obtained in good to excellent yields under eco-friendly conditions. 4,4′-Trimethylenedipiperidine is commercially available and easy to handle, and it also shows high thermal stability and good solubility in water. This work revealed that this organocatalyst, a hydrogen bond donor to active carbonyl groups and simultaneously a Lewis base through the nitrogen atom of second piperidine moiety, could play a vital role in the promotion of the one-pot multi-component reactions. The main merits of the current methodology include short reaction time, wide substrate scope, use of a metal-free catalyst and green solvents, and simple work-up process. Furthermore, this organocatalyst can be an alternative to piperidine for organic transformations.

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Organoselenium and organotellurium compounds containing chalcogen-oxygen bonds in organic synthesis or related processes

Physical Sciences Reviews ◽

10.1515/psr-2018-0061 ◽

2018 ◽

Vol 4 (5) ◽

Cited By ~ 3

Author(s):

Alexandra Pop ◽

Cristian Silvestru ◽

Anca Silvestru

Keyword(s):

Organic Synthesis ◽

Oxidation State ◽

Reaction Rate ◽

Green Solvents ◽

Organic Transformations ◽

Cyclization Reactions ◽

Chiral Species ◽

Organotellurium Compounds ◽

New Strategies

Abstract This chapter emphasizes aspects related to the role of organochalcogen (Se, Te) compounds with single E‒O and/or double E=O (E=Se, Te) bonds in organic synthesis, as reagents, intermediates, or catalysts, and it gives a larger extent mainly to data reported in the field during the last ten years. For each of these two heavier chalcogens the material is structured according to the oxidation state of the chalcogen and, for the same oxidation state, in sections dedicated to a particular type of compounds. Functionalization or cyclization reactions in which the organochalcogen compounds take part as nucleophiles, electrophiles or radicals, employed in various synthetic transformations, are discussed and, where available, the mechanistic aspects are outlined. New chiral species and new strategies were developed during last years in order to increase the yield, the reaction rate and the stereoselectivity in specific organic transformations, i.e. addition, oxidation, elimination, cyclization or rearrangement reactions. A notably attention was devoted to easily accessible and environmental friendly catalysts, re-usable and “green” solvents, as well as waste-free procedures.

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Heterogeneous Cu(ii)/l-His@Fe3O4 nanocatalyst: a novel, efficient and magnetically-recoverable catalyst for organic transformations in green solvents

RSC Advances ◽

10.1039/c6ra19776k ◽

2016 ◽

Vol 6 (95) ◽

pp. 92387-92401 ◽

Cited By ~ 11

Author(s):

Masoomeh Norouzi ◽

Arash Ghorbani-Choghamarani ◽

Mohsen Nikoorazm

Keyword(s):

Heterocyclic Compounds ◽

Green Solvents ◽

Organic Transformations ◽

Recoverable Catalyst ◽

Magnetically Recoverable Catalyst

A novel, efficient and green Cu(ii)/l-His@Fe3O4 catalyst has been applied successfully in the synthesis of heterocyclic compounds.

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Copper(II)-Bis-Cyclen Intercalated Graphene Oxide as an Efficient Two-Dimensional Nanocomposite Material for Copper-Catalyzed Azide–Alkyne Cycloaddition Reaction

Frontiers in Chemistry ◽

10.3389/fchem.2021.754734 ◽

2022 ◽

Vol 9 ◽

Author(s):

Angel Green Samuel ◽

Sowmya Subramanian ◽

Vijaikanth Vijendran ◽

Jebasingh Bhagavathsingh

Keyword(s):

Graphene Oxide ◽

Cycloaddition Reaction ◽

Interlayer Spacing ◽

Xrd Analysis ◽

Synthetic Approach ◽

Green Solvents ◽

Organic Transformations ◽

Covalent Functionalization ◽

Efficient Catalyst ◽

Ft Ir

We report stable and heterogeneous graphene oxide (GO)–intercalated copper as an efficient catalyst for the organic transformations in green solvents. The GO-intercalated copper(II) complex of bis(1,4,7,10-tetraazacyclododecane) [Cu(II)-bis-cyclen] was prepared by a facile synthetic approach with a high dilution technique. The as-prepared GO-Cu(II)-bis-cyclen nanocomposite was used as a click catalyst for the 1,3 dipolar Huisgen cycloaddition reaction of terminal alkyne and azide substrates. On directing a great deal of attention toward the feasibility of the rapid electron transfer rate of the catalyst in proliferating the yield of 1,2,3-triazole products, the click catalyst GO-Cu(II)-bis-cyclen nanocomposite was designed and synthesized via non-covalent functionalization. The presence of a higher coordination site in an efficient 2D nanocomposite promotes the stabilization of Cu(I) L-acetylide intermediate during the catalytic cycle initiated by the addition of reductants. From the XRD analysis, the enhancement in the d-interlayer spacing of 1.04 nm was observed due to the intercalation of the Cu(II)-bis-cyclen complex in between the GO basal planes. It was also characterized by XPS, FT-IR, RAMAN, UV, SEM, AFM, and TGA techniques. The recyclability of the heterogeneous catalyst [GO-Cu(II)-cyclen] with the solvent effect has also been studied. This class of GO-Cu(II)-bis-cyclen nanocomposite paves the way for bioconjugation of macromolecules through the click chemistry approach.

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