71444-37-6Relevant academic research and scientific papers
Biomass waste-derived recyclable heterogeneous catalyst for aqueous aldol reaction and depolymerization of PET waste
Khiangte, Vanlalngaihawma,Laldinpuii, Z. T.,Lalhmangaihzuala, Samson,Lalmuanpuia, Chhakchhuak,Pachuau, Zodinpuia,Vanlaldinpuia, Khiangte
, p. 19542 - 19552 (2021/11/09)
In this work, we discuss the valorization of biomass waste-derived orange peel ash (OPA) by exploring its applicability as a heterogeneous catalyst in aqueous aldol reactions and demonstrating its versatility by promoting the methanolysis of poly(ethylene terephthalate) (PET) waste. The catalyst was characterized using Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) analysis, X-ray powder diffraction (XRD), X-ray fluorescence (XRF), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and thermal gravimetric analysis (TGA) to decode its chemical composition. The aldol reactions were carried out at ambient temperature in the presence of water as a solvent. PET depolymerization was performed in an autoclave for 1 h using only 6% w/w OPA. The catalyst was recovered and reused in both the reactions for up to four successive cycles with minimal loss in the catalytic activity. The use of OPA as a cost-free, eco-friendly and effective recyclable catalyst enables a greener route for C-C bond formation and PET waste recycling.
All at once arrangement of both oxygen atoms of dioxygen into aliphatic C(sp3)-C(sp3) bonds for hydroxyketone difunctionalization
Qiao, Xiaofeng,Lin, Yuhan,Li, Jiazhen,Ma, Wanhong,Zhao, Jincai
, p. 770 - 777 (2021/04/09)
Both β- and γ- hydroxyketone structures are important units in biologically active molecules, synthetic drugs and fine chemicals. Although there are some routes available for their manufacture from pre-functionalized groups on one or two matrix molecule(s), the approaches to simply and simultaneously deposit two oxygen atoms from dioxygen into two specific C(sp3) positions of pure saturated hydrocarbons have rarely succeeded because they are involved in the targeted activation of three inert C-H σ bonds all at once. Here, we show that a TiO2-CH3CN photocatalytic suspension system enables the insertion of dioxygen into one C(sp3)-C(sp3) bond of strained cycloparaffin derivatives, by which difunctionalized hydroxyketone products are obtained in a one-pot reaction. With the cleavage event to release strain as the directional driving force, as-designed photocatalytic reaction systems show 21 examples of β-hydroxyketone products with 31%–76% isolated yields for three-membered ring derivatives and 5 examples of γ-hydroxyketone products with 30%–63% isolated yields for four-membered ring substrates. 18O isotopic labeling experiments using 18O2, Ti18O2 and intentionally added H218O, respectively, indicated that both oxygen atoms of hydroxyketone products were exclusively from dioxygen, suggesting a previously unknown H+/TiO2-e? catalyzed arrangement pathway of the hydroperoxide intermediate to convert dioxygen into hydroxyketone units. [Figure not available: see fulltext.]
Aldolase Cascade Facilitated by Self-Assembled Nanotubes from Short Peptide Amphiphiles
Afrose, Syed Pavel,Das, Dibyendu,Reja, Antara
supporting information, p. 4329 - 4334 (2020/02/05)
Early evolution benefited from a complex network of reactions involving multiple C?C bond forming and breaking events that were critical for primitive metabolism. Nature gradually chose highly evolved and complex enzymes such as lyases to efficiently facilitate C?C bond formation and cleavage with remarkable substrate selectivity. Reported here is a lipidated short peptide which accesses a homogenous nanotubular morphology to efficiently catalyze C?C bond cleavage and formation. This system shows morphology-dependent catalytic rates, suggesting the formation of a binding pocket and registered enhancements in the presence of the hydrogen-bond donor tyrosine, which is exploited by extant aldolases. These assemblies showed excellent substrate selectivity and templated the formation of a specific adduct from a pool of possible adducts. The ability to catalyze metabolically relevant cascade transformations suggests the importance of such systems in early evolution.
Preparation and characterization of magnetic graphene nanocomposite containing Cu(proline)2 as catalyst for asymmetric aldol reactions
Kooti,Kooshki,Nasiri
, p. 2641 - 2656 (2019/02/14)
A new catalyst has been prepared via immobilization of Cu(proline)2 complex onto the surface of magnetic graphene. The fabricated nanocatalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD) analysis, vibrating-sample magnetometry (VSM), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), inductively coupled plasma (ICP) techniques, and elemental analysis. Its catalytic performance was investigated in the aldol reaction using a mild and ecofriendly procedure. The synthesized nanocomposite, which contains Cu(II) center as Lewis acid, was found to be an efficient catalyst for asymmetric aldol reactions, affording corresponding aldol products in high yield and excellent enantiomeric excess (> 90?%). The examined catalyst was prepared from low-cost, easily available starting materials and can be readily isolated by magnetic decantation for recycling and reuse in consecutive reactions without significant loss of activity.
The Complete Mechanism of an Aldol Condensation
Perrin, Charles L.,Chang, Kuei-Lin
, p. 5631 - 5635 (2016/07/13)
Although aldol condensation is one of the most important organic reactions, capable of forming new C-C bonds, its mechanism has never been fully established. We now conclude that the rate-limiting step in the base-catalyzed aldol condensation of benzaldehydes with acetophenones, to produce chalcones, is the final loss of hydroxide and formation of the C=C bond. This conclusion is based on a study of the partitioning ratios of the intermediate ketols and on the solvent kinetic isotope effects, whereby the condensations are faster in D2O than in H2O, regardless of substitution.
One-pot bienzymatic cascade combining decarboxylative aldol reaction and kinetic resolution to synthesize chiral β-hydroxy ketone derivatives
Xu, Fan,Xu, Jian,Hu, Yujing,Lin, Xianfu,Wu, Qi
, p. 76829 - 76837 (2016/08/30)
A bienzymatic one-pot sequential cascade for the synthesis of (S)-β-hydroxy ketones and acylated (R)-β-hydroxy ketone derivatives was successfully developed. An immobilized lipase from Mucor miehei (MML) catalysed promiscuous decarboxylative aldol reaction and a lipase A or B from Candida antarctica (CAL-A or CAL-B) catalysed kinetic resolution of racemic β-hydroxy ketone were combined in this one-pot protocol, reducing the purification step between the two reactions. Twelve chiral β-hydroxy ketones and the same number of corresponding acylated derivatives were obtained with excellent ee values and high yields through this method, and the scaling up experiment also worked without apparent loss of reaction rate and stereoselectivity.
PH-Tuned modulation of 1d chain to 3d metal-organic framework: Synthesis, structure and their useful application in the heterogeneous claisen-Schmidt reaction
Sen, Rupam,Saha, Debraj,Koner, Subratanath,Mal, Dasarath,Brando, Paula,Lin, Zhi
, p. 591 - 598 (2015/03/14)
The role of pH in the formation of metal-organic frameworks (MOFs) has been studied on magnesium-based carboxylate framework systems [Mg(Pdc)(H2O)3]n (1) and [Mg(Pdc)(H2O)]n (2) (Pdc=pyridine-2,3-dica
Cage Like Al-KIT-5 Mesoporous Materials for C-C Bond Formation Reactions under Solvent Free Conditions
Baruah, Pranjal K.,Dutta, Prantu,Kalita, Pranjal
, p. 2037 - 2045 (2015/12/24)
The C-C bond forming reactions are of fundamental importance in chemistry. As a result there is ever growing interest for chemists to develop new methods for C-C bond formation. We report here three dimensional nano-cage mesoporous aluminosilicate materia
Synthesis of axially chiral 1,8-diarylnaphthalene ligands and application in asymmetric catalysis: An intriguing fluorine effect
Ghosh, Harisadhan,Vavilala, Ravishashidhar,Szpilman, Alex M.
, p. 79 - 84 (2015/02/19)
A fluorinated and a non-fluorinated axially chiral 1,8-diarylnaphthalene ligand have been synthesized through an Ullmann and Suzuki coupling reaction based strategy. A practical methodology for the successful chiral resolution of the newly synthesized catechol based moiety is presented. We also disclose the preliminary application of these axially chiral molecules as ligands in asymmetric transformation reactions.
Alkaline earth metal-based metal-organic framework: Hydrothermal synthesis, X-ray structure and heterogeneously catalyzed Claisen-Schmidt reaction
Saha, Debraj,Maity, Tanmoy,Koner, Subratanath
, p. 13006 - 13017 (2014/08/18)
Two alkaline earth metal-based carboxylate systems, [Mg(HL)(H 2O)2]n (1) and [Ca(H2L) 2]n (2) (H3L = chelidamic acid) have been hydrothermally synthesized, and characterized by single-crystal X-ray diffraction, IR, elemental analysis, and thermo-gravimetric analysis. Compound 1 has a 2D structure incorporating two water molecules. The dehydrated species, 1a, generated from 1 by removal of the coordinated water, has been characterized by thermo-gravimetric analysis, IR, elemental analysis and variable temperature powder X-ray diffraction. Both 1 and its dehydrated species 1a catalyze the Claisen-Schmidt reaction under heterogeneous conditions, but 1a is a more effective catalyst under environmentally friendly conditions. The catalyst can readily be recovered and reused in successive cycles without detectable loss of activity. Compound 2 has a 3D structure and is thermally stable up to 540 °C, but is inactive catalytically. This journal is the Partner Organisations 2014.
