Aromatic Ketones Research Articles

Electrochemical deoxygenative arylation of aldehydes and ketones.

The construction of diaryl alkanes from aromatic aldehydes or ketones with electron-deficient arenes is achieved in the presence of trivalent phosphine under electrochemical conditions. Reductive coupling between electron-deficient arenes and the carbonyl groups of aldehydes or ketones occurs at the cathode to yield diaryl alcohols. At the anode, the trivalent phosphine reagent may undergo single-electron oxidation to generate its radical cation, which reacts with the diaryl alcohols to form dehydroxylated products.

Protein engineering of multi-enzyme virus-like particle nanoreactors for enhanced chiral alcohol synthesis.

In the past decade, virus-like particles (VLPs) that can encapsulate single or multiple enzymes have been studied extensively as typical nanoreactors for biocatalysis in vitro, yet their catalytic efficiencies are usually inadequate for real applications. These biocatalytic nanoreactors should be engineered like their free-enzyme counterparts to improve their catalytic performance for potential applications. Herein we engineer biocatalytic VLPs for the enhanced synthesis of chiral alcohols. Different methods including directed evolution were applied to the entire bacteriophage P22 VLPs (except the coat protein), which encapsulated a carbonyl reductase from Scheffersomyces stipitis (SsCR) and a glucose dehydrogenase from Bacillus megaterium (BmGDH) in their capsids. The best variant, namely M5, showed an enhanced turnover frequency (TOF, min-1) up to 15-fold toward the majority of tested aromatic prochiral ketones, and gave up to 99% enantiomeric excess in the synthesis of chiral alcohol pharmaceutical intermediates. A comparison with the mutations of the free-enzyme counterparts showed that the same amino acid mutations led to different changes in the catalytic efficiencies of free and confined enzymes. Finally, the engineered M5 nanoreactor showed improved efficiency in the scale-up synthesis of chiral alcohols. The conversions of three substrates catalyzed by M5 were all higher than those catalyzed by the wild-type nanoreactor, demonstrating that enzyme-encapsulating VLPs can evolve to enhance their catalytic performance for potential applications.

Microwave Assisted Synthesis, Characterisation and Biological Activities of Cu(II) Complexes of Few Thiosemicarbazones Ligands

Thiosemicarbazones are class of compounds which are obtained by the condensation of thiosemicarbazide with carbonyl compounds. The transition metal complexes of thiosemicarbazones are widely considered due to their broad spectrum of biological activities such as antibacterial, antitumor and antifungal activities. In present research work a series of four novel Cu(II) aryl thiosemicarbazones complexes having the general composition [Cu(L1)2Cl2], [Cu(L2)2Cl2], [Cu(L3)2Cl2] and [Cu(L4)2Cl2]{where L1= 4-nitroacetophenone thiosemicarbazones (4NAT), L2 = 3-nitrobenzaldehyde thiosemicarbazone (3NBT), L3 = 4-hydroxybenzaldehyde thiosemicarbazone (4HBT) and L4 = 4-aminoacetophenone thiosemicarbazone (4AAT)} have been synthesized by the reaction of thiosemicarbazide with substituted aromatic aldehydes and ketones by conventional heating as well as microwave irradiations method followed by complexation with Cu(II) metal. The synthesized compounds have been characterised by elemental analysis, melting point determination, FTIR, UV-visible spectral analysis. Thiosemicarbazone ligands behave as bidentate ligand and forms octahedral complexes with Cu(II). The synthesized ligands and their new metal complexes have been screened in vitro for antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis bacteria. The result shows that all the Cu(II) complexes are potent antibacterial agents against these bacteria.

Enhanced ORR performance to electrochemical lignin valorization in a mixture of ionic liquid/organic solvent binary electrolytes

Only 4 kinds of small molecule aromatic aldehydes and ketones observe after lignin electrochemical conversion, which demonstrates better selectivity in cleavage of the ether bonds attacked by superoxide radicals through controlling ORR in the binary electrolyte [BMIM]BF4/CH3CN.

Brønsted acid-catalysed aerobic photo-oxygenation of benzylic C–H bonds

Herein, we reported a Brønsted acid-promoted aerobic photo-oxygenation of benzylic C–H bonds to construct aromatic carboxylic acids and ketones under mild conditions.

A 1,2,3-triazole-derived pincer-type mesoionic carbene complex of iron(II): carbonyl elimination and hydrosilylation of aromatic aldehydes via the concerted reaction with hydrosilane and a base.

Iron complexes bearing 1,2,3-triazol-5-ylidene were synthesized and applied to the reaction with hydrosilane and homogeneous catalytic hydrosilylation of aromatic ketones and aldehydes. Addition of a free carbene to a solution of Fe(CO)4Br2 yielded an octahedral, diamagnetic and cationic iron(II) complex [Fe(1,2,3-triazolylidene)(CO)2Br]+. Pyrolysis of the dicarbonyl complex eliminated the two CO ligands to form a paramagnetic four-coordinate complex. A theoretical study using DFT calculations indicated that the spin state changed from singlet to quintet during ligand elimination. Investigations of the successful hydrosilylation of acetophenone and benzaldehyde derivatives using MIC-iron(II) bromide suggested the importance of the base for efficient conversion in the catalytic process. The bromide-to-hydride exchange reaction, transmetallation, of MIC-iron(II) bromide in the presence of KOtBu and HSi(OEt)3 which could occur in the initial process of hydrosilylation was proposed, and supported by a theoretical study.

Dioxygen-triggered oxidation of benzylic C–H bonds: insight on the synergistic effect of Cu–Fe bimetallic oxide

A cubic Fe–Cu bimetallic oxide with excellent redox property was fabricated. It exhibited good aerobic benzylic C–H oxidation performance under ambient conditions, highlighting new opportunities to produce aromatic ketones.

Magnetic MoS2 efficient heterogeneous photocatalyst for the α-methoxymethylation and aminomethylation of aromatic ketones

Magnetic MoS2 quantum dots are designed and applied as an efficient photocatalyst for the α-methoxymethylation and aminomethylation of aromatic ketones using methanol as a green C1 source in air under visible-light irradiation at room temperature.

3,5-Bis(trifluoromethyl) phenylammonium triflate: a new and green organocatalyst for the synthesis of indeno[1,2?b]pyridines

3,5-Bis(trifluoromethyl) phenyl ammonium triflate(BFPAT) catalyzed one-pot synthesis of indeno[1,2-b]pyridine compound derivatives by four-component condensation of aldehyde, aromatic ketones, 1,3-indanedione, and ammonium acetate in ethanol. Accessible starting materials, Simplicity of operation, green and practical catalyst, easy purification, and excellent yields are the key benefits of the current technique.

One-Electron Oxidant-Induced Transformations of Aromatic Alcohol to Ketone Moieties in Dissolved Organic Matter Increase Trichloromethane Formation.

Radicals in advanced oxidation processes (AOPs) degrade micropollutants during water and wastewater treatment, but the transformation of dissolved organic matter (DOM) may be equally important. Ketone moieties in DOM are known disinfection byproduct precursors, but ketones themselves are intermediates produced during AOPs. We found that aromatic alcohols in DOM underwent transformation to ketones by one-electron oxidants (using SO4•- as a representative), and the formed ketones significantly increased trichloromethane (CHCl3) formation potential (FP) upon subsequent chlorination. CHCl3-FPs from aromatic ketones (Ar-CO-CH3, average of 22 mol/mol) were 6-24 times of CHCl3-FPs from aromatic alcohols (Ar-CH(OH)-CH3, average of 0.85 mol/mol). At a typical SO4•- exposure of 7.0 × 10-12 M·s, CHCl3-FPs from aromatic alcohol transformation increased by 24.8%-112% with an average increase of 53.4%. Notably, SO4•- oxidation of aliphatic alcohols resulted in minute changes in CHCl3-FPs due to their low reactivities with SO4•- (∼107 M-1 s-1). Other one-electron oxidants (Cl2•-, Br2•-,and CO3•-) are present in AOPs and also lead to aromatic alcohol-ketone transformations similar to SO4•-. This study highlights that subtle changes in DOM physicochemical properties due to one-electron oxidants can greatly affect the reactivity with free chlorine and the formation of chlorinated byproducts.

Antiandrogenic and Estrogenic Activity Evaluation of Oxygenated and Nitrated Polycyclic Aromatic Hydrocarbons Using Chemically Activated Luciferase Expression Assays.

To establish the risk of the endocrine disrupting activity of polycyclic aromatic compounds, especially oxygenated and nitrated polycyclic aromatic hydrocarbons (oxy-PAHs and nitro-PAHs, respectively), antiandrogenic and estrogenic activities were determined using chemically activated luciferase expression (CALUX) assays with human osteoblast sarcoma cells. A total of 27 compounds including 9 oxy-PAHs (polycyclic aromatic ketones and quinones) and 8 nitro-PAHs was studied. The oxy-PAHs of 7H-benz[de]anthracen-7-one (BAO), 11H-benzo[a]fluoren-11-one (B[a]FO), 11H-benzo[b]fluoren-11-one (B[b]FO), and phenanthrenequinone (PhQ) exhibited significantly the potent inhibition of AR activation. All nitro-PAHs exhibited high antiandrogenic activities (especially high for 3-nitrofluoranthene (3-NFA) and 3-nitro-7H-benz[de]anthracen-7-one (3-NBAO)), and the AR inhibition was confirmed as noncompetitive for 3-NFA, 3-NBAO, and 1,3-dinitropyrene (1,3-DNPy). Antiandrogenic activity of 3-NFA demonstrated characteristically a U-shaped dose-response curve; however, the absence of fluorescence effect on the activity was confirmed. The prominent estrogenic activity dependent on dose-response curve was confirmed for 2 oxy-PAHs (i.e., B[a]FO and B[b]FO). Elucidating the role of AR and ER on the effects of polycyclic aromatic compounds (e.g., oxy- and nitro-PAHs) to endocrine dysfunctions in mammals and aquatic organisms remains a challenge.

Photocatalytic Oxidative Cleavage of Alkenes by Molecular Oxygen: Reaction Scope, Mechanistic Insights, and Flow Application.

The oxidative cleavage of C═C bonds with molecular oxygen was promoted effectively by a catalytic amount of a decatungstate photocatalyst using black light irradiation (365 nm). Not only aromatic ketones but also aliphatic ketones were obtained by the photocatalytic protocol. The continuous flow reaction of α-methylstyrene using a high-power ultraviolet light-emitting diode (365 nm) dramatically decreased the reaction time.

The Murai Reaction: ortho-Directed Ruthenium-Catalyzed C–H Alkylation of Aromatic Ketones

The Murai Reaction: ortho-Directed Ruthenium-Catalyzed C–H Alkylation of Aromatic Ketones

Investigation of enhanced H2 production from municipal solid waste gasification via artificial neural network with data on tar compounds

An artificial neural network (ANN) is a biologically inspired computational technique that imitates the behavior and learning process of the human brain. In this study, ANN technique was applied to assess the gasification of municipal solid waste (MSW) with the aim of enhancing the H2 production. The experiments were conducted using a horizontal tube reactor under different parameters: temperatures, MSW loadings, residence times, and equivalence ratios. The input and output variables (released gases) were tested and trained using back-propagation algorithm, and the data distribution by K-fold contrivance. The values of the training (80% data) and validation (20% data) dataset were found satisfactory. The values of regression coefficient (R2) for the training phase were lied between 0.9392 and 0.9991, and 0.9363 and 0.993824 for the testing phase. Whereas; the values of root mean square error (RSME) for the training phase were lied between 0.4111 and 0.8422, and between 0.1476 and 0.7320 for the testing phase. Higher H2 production of 42.1 vol% was produced at the higher reaction temperature of 900 °C with LHV of 11.2 MJ/Nm3. According to the tar analysis, the dominant compounds were aromatics (17 compounds) followed by polycyclic aromatic, phenyl, aliphatic, aromatic heterocyclic, polycyclic, and aromatic ketone compounds.

Structure of the Reductase Domain of a Fungal Carboxylic Acid Reductase and Its Substrate Scope in Thioester and Aldehyde Reduction.

The synthesis of aldehydes from carboxylic acids has long been a challenge in chemistry. In contrast to the harsh chemically driven reduction, enzymes such as carboxylic acid reductases (CARs) are considered appealing biocatalysts for aldehyde production. Although structures of single- and didomains of microbial CARs have been reported, to date no full-length protein structure has been elucidated. In this study, we aimed to obtain structural and functional information regarding the reductase (R) domain of a CAR from the fungus Neurospora crassa (Nc). The NcCAR R-domain revealed activity for N-acetylcysteamine thioester (S-(2-acetamidoethyl) benzothioate), which mimics the phosphopantetheinylacyl-intermediate and can be anticipated as the minimal substrate for thioester reduction by CARs. The determined crystal structure of the NcCAR R-domain reveals a tunnel that putatively harbors the phosphopantetheinylacyl-intermediate, which is in good agreement with docking experiments performed with the minimal substrate. In vitro studies were performed with this highly purified R-domain and NADPH, demonstrating carbonyl reduction activity. The R-domain was able to accept not only a simple aromatic ketone but also benzaldehyde and octanal, which are typically considered to be the final product of carboxylic acid reduction by CAR. Also, the full-length NcCAR reduced aldehydes to primary alcohols. In conclusion, aldehyde overreduction can no longer be attributed exclusively to the host background.

In-vitro and In-vivo Identification, Absorbtion and Metabolism Network Analysis of Filifolium sibiricum Flavonoids Dropping Pill by UHPLC-Q-TOF-MS.

Filifolium sibiricum flavonoids dropping pill (FSFp), a unique Chinese Filifolii sibirici herba extract preparation, has the potential as an alternative therapy against S. aureus infection (SA) and antiinfection. However, its chemical composition and in vivo metabolism characteristics remain unknown, which limits its clinical application. Here, we aimed to understand the in vitro and in vivo material basis of FSFp. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) was used to identify chemicals in FSFp as well as its phase I and phase II reaction metabolites in plasma, urine and feces. A total of 38 chemicals were characterized in FSFp, including 22 flavonoids, 10 organic acids, 3 chromones, 1 aromatic ketone, 1 coumarin, and 1 ligan. After analysis of the drugged bio-samples, a total of 21 compounds were found in urine, and 16 of them were found in feces, but only one was found in plasma. In addition, 56 FSFp-related metabolites were characterized, of which 56 were in urine, 4 in feces, and 8 in plasma. This is the first comprehensive research of FSFp on chemical constituents and metabolic profiles. It was expected that this study would offer reliable support for further investigation of FSFp.

Annulation of m-Substituted Aromatic Ketones with Diphenylacetylene Catalyzed by Ruthenium: A Reliable Route to Substituted Naphthalene Derivatives

Annulation of m-Substituted Aromatic Ketones with Diphenylacetylene Catalyzed by Ruthenium: A Reliable Route to Substituted Naphthalene Derivatives

Novel chalcone scaffolds of benzothiophene as an efficient real time hydrazine sensor: Synthesis and single crystal XRD studies

Continue to our on-going research, this article demonstrate the design and development of an efficient real time hydrazine sensor. A series of novel chalcone scaffolds are synthesised by the reaction of benzothiophene-3-aldehyde with various aromatic poly-nuclear hetero-aryl ketones. Theorized molecules are synthesised via the classical Claisen Smidt condensation. This condensation is illustrated by use of KOH and pyrrolidine as a catalyst to develop two different protocols with competitive studies. The obtained results suggest KOH as a quick catalyst however pyrrolidine as an efficient catalyst. Structure of prepared molecules are confirmed by various spectral analysis and single crystal XRD studies. Solvent screening study shows methanol as more appropriate solvent for UV–Visible absorption and fluorescence emission properties. Based on this study, an effecient real-time hydrazine sensing protocol is established with selected one molecule. A detailed process with working pH range, sensing selectivity among other analytes, soil sample test is developed and demonstrated. The studied chalcone has shown good working pH range and excellent selectivity for hydrazine. The possible mechanism for the detection of hydrazine is also confirmed by spectral analysis and discussed here. We are looking forward to fabricate the prototype devise for hydrazine detection in real life applications.

Organocatalyzed One‐Pot Sequential Deracemization of Aromatic Ketones Bearing a Tertiary Stereogenic Center

AbstractAn organocatalyzed one‐pot sequential deracemization of aromatic ketones bearing a stereogenic center at the α‐position was achieved thanks to an acid‐base strategy involving an enantioselective protonation reaction as a key step. This simple and efficient protocol yields enantioenriched ketones in up to 89% ee without the need to isolate sensitive intermediates such as silyl enolates. The key role of water in this process was underlined. This one‐pot sequence constitutes a useful extension to previously reported chemically driven red‐ox protocols, thus increasing the panel of molecules eligible to a deracemization strategy.magnified image

Effect of the Position and Amount of the Electron‐Donating Groups in Substituted 2,4,6‐Triphenylpyrimidines on their Thermal, Optical and Electrochemical Properties

Abstract2,4,6‐Triphenylpyrimidine derivatives have been synthesized from the corresponding aromatic aldehydes and methyl ketones via a two‐step procedure, which include an aldol‐crotonic condensation followed by the reaction of the resulting chalcones with ammonium acetate in the presence of a catalytic amount of trifluoromethanesulfonic acid with DMF as a solvent The compound structures have been identified by NMR and IR spectroscopy and elemental analysis. The thermal, optical and electrochemical properties of the compounds obtained have been studied. The synthesized 2,4,6‐triphenylpyrimidines are characterized by blue emission. It has been shown, that these compounds have narrow band gaps and high fluorescence quantum yields.