Solvent-Free Henry and Michael Reactions with Nitroalkanes Promoted by Potassium Carbonate as a Versatile Heterogeneous Catalyst

Bosica, Giovanna; Polidano, Kurt

doi:10.1155/2017/6267036

Cited by 8 publications

(5 citation statements)

References 28 publications

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“…If a primary nitroalkane or nitromethane are selected as reactants, acidic protons will still remain in the nitroalcohol after the addition reaction, making it possible for the water elimination to give rise to nitroalkenes, which correspond to the major secondary product of the Henry reactions under the studied conditions. Thus, a small amount of base and low to moderate temperatures must be used in order to achieve good selectivity for the β-nitroalcohol compounds [60,61]. Typically, an excess of the nitroalkane is added in this equilibrium reaction to ensure the formation of the nitroalcohols in good yields, since they are important building blocks and precursors of a wide variety of other longer-chain compounds, endowed with functional groups essential in chemical synthesis and with biological relevance [62,63].…”

Section: Catalytic Performance In Henry Reactionmentioning

confidence: 99%

Triazine-Based Porous Organic Polymers: Synthesis and Application in Dye Adsorption and Catalysis

2023

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The scientific community has been developing promising materials to increase the sustainability and efficiency of production processes and pollutant environmental remediation strategies. Porous organic polymers (POPs) are of special interest, as they are insoluble custom-built materials at the molecular level, endowed with low densities and high stability, surface areas, and porosity. This paper describes the synthesis, characterization, and performance of three triazine-based POPs (T-POPs) in dye adsorption and Henry reaction catalysis. T-POPs were prepared by a polycondensation reaction between melamine and a dialdehyde (terephthalaldehyde (T-POP1) or isophthalaldehyde derivatives with a hydroxyl group (T-POP2) or both a hydroxyl and a carboxyl group (T-POP3)). The crosslinked and mesoporous polyaminal structures, with surface areas between 139.2 and 287.4 m2 g−1, positive charge, and high thermal stability, proved to be excellent methyl orange adsorbents, removing the anionic dye with an efficiency >99% in just 15–20 min. The POPs were also effective for methylene blue cationic dye removal from water, reaching efficiencies up to ca. 99.4%, possibly due to favorable interactions via deprotonation of T-POP3 carboxyl groups. The modification of the most basic polymers, T-POP1 and T-POP2, with copper(II) allowed the best efficiencies in Henry reactions catalysis, leading to excellent conversions (97%) and selectivities (99.9%).

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Section: Catalytic Performance In Henry Reactionmentioning

confidence: 99%

Triazine-Based Porous Organic Polymers: Synthesis and Application in Dye Adsorption and Catalysis

2023

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“…Only a small change to the original procedure was necessary for hydro cinnamaldehyde 2d (Table 1, entry 4), which required 15mol% of TMG to provide an 90% yield of the corresponding βnitro alcohol 3d. Regarding reactivity, we found that aliphatic linear aldehydes were more reactive towards this transformation with respect to their branched or aromatic counterparts (Concellón et al, 2006;Bosica and Polidano, 2017). We tested aromatic aldehydes, both benzaldehyde (Table 1, entry 5) and furfural (Table 1, entry 6), but they did not provide sufficient yields after the first transformation due to possible elimination of water and the formation of the corresponding nitroolefins.…”

Section: Strategy and Synthesis Of β-Hydroxy Aminesmentioning

confidence: 99%

Novel terephthalamide diol monomers synthesis from PET waste to Poly(Urethane acrylates)

et al. 2023

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Due to its excellent properties, poly(ethylene terephthalate) (PET) is one of the most produced and consumed polymers. Among plastics, it represents the main contributor to environmental pollution. Following the circular economy model, the chemical upcycling of PET reduces the amount of waste generated and transforms it into high-value products. The depolymerization of poly(ethylene terephthalate) into oligomers or monomers leads to forming a library of reactive molecules involved in different polymerization processes to obtain compounds with improved properties. Herein, several β-hydroxy amines were synthesized and used for the chemical recycling of water bottle waste by an environmental benefit aminolysis process to get very useful new terephthalamide diol monomers. The recycled diol monomers were subsequently exploited to synthesize poly(urethane acrylates) (PUAs) UV-curable coatings, and their chemical, thermal and mechanical characterizations were performed. The results show the great potential of the developed synthesis protocols to obtain PUAs with final properties that can be modulated to meet the requirements of different applications.

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“…9−20 Chemical catalysts often need cryogenic conditions, dry solvents, and/or hazardous metals to meet the required stereocontrol synthesis 9,13,17 and are known to associate with side reactions, e.g., retro-Henry and Cannizzaro reaction. 9,21,22 Biocatalysis offers sustainable technology along with high selectivity and efficiency to the synthesis of diverse chemical structural units. Despite numerous advantages, there exist limited biocatalytic transformations for the diastereoselective synthesis of β-nitroalcohols.…”

Section: ■ Introductionmentioning

confidence: 99%

Uncovering Hydroxynitrile Lyase Variants with Promiscuous Diastereoselective Nitroaldolase Activity toward the Highly Stereocontrolled Synthesis of Anti β-Nitroalcohols

Chatterjee,

Priyanka,

Prabhu

et al. 2024

ACS Catal.

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Diastereoselective Henry reaction (DHR) is an effective direct C−C bond ligation transformation that enables the synthesis of β-nitroalcohols having two contiguous chiral centers. Despite significant applications of optically active β-nitroalcohol diastereomers as key chiral intermediates for the synthesis of important pharmaceuticals and biologically active molecules, the biocatalytic asymmetric Henry reaction remains underdeveloped. Here, we show thatArabidopsis thaliana hydroxynitrile lyase (AtHNL) variants with single amino acid substitution, Y14C and Y14A, empower promiscuous DHR with a broad synthetic scope toward different aldehydes and nitroalkane and high enantio-and diastereoselectivity (up to >99% ee, >99% de, >99% ic, and ∼3470 total turnover number) in the production of diverse anti (1R,2S)-β-nitroalcohols. Y14C displayed a remarkable >250-fold increase in catalytic efficiency to that of the wild-type toward stereoselective nitroethane addition to benzaldehyde. A gram-scale biocatalysis was illustrated using readily available benzaldehyde and nitroethane followed by a one-step chemical reduction of the product to prepare L-norephedrine, a therapeutic, with >99% ee and de. The origin of the anti diastereoselectivity was probed using computational studies and isotope labeling experiments. This study describes the uncovering of variants providing a simple, sustainable, and economical biocatalytic platform for the synthesis of a repertoire of anti-β-nitroalcohol diastereomers of structural diversity with excellent stereocontrol.

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Solvent-Free Henry and Michael Reactions with Nitroalkanes Promoted by Potassium Carbonate as a Versatile Heterogeneous Catalyst

Cited by 8 publications

References 28 publications

Triazine-Based Porous Organic Polymers: Synthesis and Application in Dye Adsorption and Catalysis

Triazine-Based Porous Organic Polymers: Synthesis and Application in Dye Adsorption and Catalysis

Novel terephthalamide diol monomers synthesis from PET waste to Poly(Urethane acrylates)

Uncovering Hydroxynitrile Lyase Variants with Promiscuous Diastereoselective Nitroaldolase Activity toward the Highly Stereocontrolled Synthesis of Anti β-Nitroalcohols

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