Ketone Moiety Research Articles

Catalytic Formation of Ketones from Unactivated Esters through Rhodium Chelation-Assisted C–O Bond Activation

A new method for building aryl aryl ketones containing heterocyclic rings through chelation-assisted C-O bond activation catalyzed by a rhodium complex has been developed. In this reaction, methyl quinoline-8-carboxylate, methyl quinoxaline-5-carboxylate, and their derivatives were reacted with an excess amount of a substituted phenyl boronic acid in the presence of a rhodium(I) complex to give substituted phenyl(quinolin-8-yl)methanone, phenylquinoxalin-5-ylmethanone, and their derivatives in medium to high yields. The current method offers a highly favorable synthetic pathway to efficiently build related drugs with an 8-benzoylquinoline core structure. This method may prove especially valuable for medicinal chemists for the late-stage introduction of versatile ketone moieties into complex scaffolds for diversity-oriented synthetic strategies.

Structure-Dependent Complexation of Fe3+ by Anthracyclines. 1. The Importance of Pendent Hydroxyl Functionality

We have investigated the stability of doxorubicin and daunorubicin complexes with Fe(3+) in aqueous solution. Doxorubicin and daunorubicin are anthracycline chemotherapeutic agents that differ structurally by the presence of a hydroxymethylketone functionality in doxorubicin versus a methyl ketone moiety in daunorubicin. We demonstrate that the presence of the hydroxyl group in doxorubicin enhances its 1:1 complexation with Fe(3+) relative to that seen for daunorubicin. We utilize UV-visible absorbance, circular dichroism, fluorescence and EPR spectroscopies, molecular dynamics, and semiempirical calculations to understand how the presence of an additional hydroxyl group affects the interactions of anthracyclines with Fe(3+). Our data indicate that the binding mode of iron in the complex is different for doxorubicin and daunorubicin.

Induction of quinone reductase (QR) by withanolides isolated from Physalis pubescens L. (Solanaceae)

In the present study, it was demonstrated that the dichloromethane extract of Physalis pubescens L. (DEPP) had weak potential quinone reductase (QR) inducing activity, but an UPLC–ESI-MS method with glutathione (GSH) as the substrate revealed that the DEPP had electrophiles (with an α,β-unsaturated ketone moiety). These electrophiles could induce quinone reductase (QR) activity, which might be attributed to the modification of the highly reactive cysteine residues in Keap1. Herein, four withanolides, including three new compounds physapubescin B (2), physapubescin C (3), physapubescin D (4), together with one known steroidal compound physapubescin (1) were isolated. Structures of these compounds were determined by spectroscopic analysis and that of physapubescin C (3) was confirmed by a combination of molecular modeling and quantum chemical DFT-GIAO calculations. Evaluation of the QR inducing activities of all withanolides indicated potent activities of compounds 1 and 2, which had a common α,β-unsaturated ketone moiety.

ChemInform Abstract: Palladium‐Catalyzed ortho‐CH‐Bond Oxygenation of Aromatic Ketones.

A palladium-catalyzed C(sp2)–H bond oxygenation reaction is described. This protocol represents the first example of a C–H bond cleavage/C–O bond formation sequence, by employing a ketone moiety as the directing group. With this new catalytic method, a variety of ortho-acylphenols can be easily accessed from arylketones.

High modulus and high strength ultra-thin polyimide films with hot-stretch induced molecular orientation

This paper concerns uniaxially stretched ultra-thin polyimide (PI) films containing ether and ketone moieties. The stretched PI films exhibited remarkable high modulus (4.9 GPa) and high strength (258 MPa) in the stretch direction compared with commercial polyimides because of their high degree of molecular orientation induced by uniaxial hot stretch. The tensile strength of the stretched PI films is about 2.4 times of that of undrawn films and the coefficients of thermal expansion decreased by as much as 84%. Studies of birefringence and wide-angle X-ray diffraction all proved a high degree of molecular orientation and crystallization induced during the drawing process. The thickness of stretched PI films was reduced at least 75% as compared to unstretched PI films and the thinnest film is only 7 μm.

Quantification of fatty acid oxidation products using online high-performance liquid chromatography tandem mass spectrometry

Oxidized fatty acids formed via lipid peroxidation are implicated in pathological processes such as inflammation and atherosclerosis. A number of methods may be used to detect specific oxidized fatty acids containing a single or multiple combinations of epoxide, hydroxyl, ketone, and hydroperoxide moieties on varying carbon chain lengths from C8 up to C30. Some of these methods are nonspecific and their use in biological systems is fraught with difficulty. Measures of specific oxidized fatty acid derivatives help in identifying oxidation pathways in pathological processes. We used liquid chromatography coupled with electrospray ionization tandem mass spectrometry as an efficient, selective, and sensitive method for identifying and analyzing multiple specific fatty acid peroxidation products in human plasma and other biological matrices. We then distilled the essential components of a number of these analyses to provide an efficient protocol by which fatty acid oxidation products and their parent compounds can be determined. In this protocol, addition of a synthetic internal standard to the sample, followed by base hydrolysis at elevated temperature and liquid–liquid phase sample extraction with lighter-than-water solvents, facilitates isolation of the oxidized fatty acid species. These species can be identified and accurately quantified using stable-isotope dilution and multiple-reaction monitoring. Use of a coupled multiplexed gradient HPLC system on the front end enables high-throughput chromatography and more efficient use of mass spectrometer time.

ChemInform Abstract: Dioxirane‐Mediated Heterogeneous Epoxidations with Potassium Caroate: A Solid Catalyst Bearing Anchored Ketone Moieties.

AbstractThe hybrid material HSC, containing trifluoromethyl ketone moieties anchored on silica gel through a short spacer, is used in efficient heterogeneous epoxidations using potassium caroate.

ChemInform Abstract: A Regio‐ and Diastereoselective Palladium‐Catalyzed Cyclopropanation of Norbornene Derivatives with Molecular Oxygen as the Sole Oxidant.

AbstractThe title reaction allows the highly regio‐ and diastereoselective assembly of various 1,2,3‐trisubstituted cyclopropanes(III), (V), (VII), (IX), and (XI) bearing α,β‐unsaturated ketone moieties.

Synthesis, thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene‐ether)esters containing α,β‐unsaturated ketone moiety in the main chain

AbstractA series of poly(benzylidene‐ether)esters containing a photoreactive benzylidene chromophore in the main chain were synthesized from 2,6‐bis(4‐hydroxy‐3‐methoxybenzylidene)cyclohexanone (BHMBCH) with various aliphatic and aromatic diacid chlorides by an interfacial polycondensation technique. The intrinsic viscosity of the synthesized homo and copolymers determined by Ubbelohde viscometer was found to be 0.12 to 0.17 dL/g. The molecular structure of the monomer and polymers was confirmed by FT‐IR, 1H NMR, and 13C NMR spectral analyses. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the polymers were stable up to 280 °C and start degrading thereafter. Increase in acid methylene spacer length decreased the thermal stability. The self‐extinguishing property of the synthesized polymers was studied by calculating the limiting oxygen index (LOI) value using a Van Krevelen's equation. The influence of the length of methylene spacer on phase transition was investigated using DSC and odd‐even effect has been observed. Hot‐stage optical polarizing microscopic (HOPM) study showed that most of the polymers exhibited birefringence and opalescence properties. The photolysis of liquid crystalline poly(benzylidene‐ether)esters revealed that α,β‐unsaturated ketone moiety in the main chain dimerises through 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Palladium-Catalyzed ortho-CH-Bond Oxygenation of Aromatic Ketones

A palladium-catalyzed C((sp2))-H bond oxygenation reaction is described. This protocol represents the first example of a C-H bond cleavage/C-O bond formation sequence, by employing a ketone moiety as the directing group. With this new catalytic method, a variety of ortho-acylphenols can be easily accessed from arylketones.

Radical Photocyclization Route for Macrocyclic Lactone Ring Expansion and Conversion to Macrocyclic Lactams and Ketones

A new method for the synthesis of macrocyclic lactones, lactams, and ketones, which utilizes photoinduced intramolecular radical cyclization reactions of substrates containing tethered carboxylic acids and α,β-unsaturated carbonyl moieties, has been uncovered. Photocyclization of the carboxylic acids tethered acrylate ester, which were prepared starting from the macrocyclic lactones, gave the two-carbon elongated macrocyclic lactones via decarboxylation. Similar photoreactions of carboxylic acid tethered acryl amide or α,β-unsaturated ketone moieties, which were also prepared starting from the macrocyclic lactones, produced macrocyclic lactams or ketones, respectively. The simple approach can be readily applied to the preparation of a variety of macrocyclic lactones, lactams, and ketones with tunable ring sizes.

One-pot reduction of olefin and ketone moieties by a copper–phosphine catalyst enabled by polar aprotic solvents

One-pot reduction of both olefin and ketone moieties in a non-food biomass derived substrate using simple copper–phosphine catalysts is described. The electron rich, sterically unencumbered bis(diethylphosphino)ethane ligand used here gives an 84% yield of the product where both the olefin and ketone have been reduced in minutes using PhSiH3 and dry acetonitrile as the solvent. The coordinating ability of acetonitrile appears to be critical for effecting this one-pot reduction. Labeling experiments indicate that ketone reduction in benzene occurs predominantly via a sigma bond metathesis pathway.

Synthesis and Antiproliferative Effect of Novel Curcumin Analogues

Novel curcumin analogues with α,β-unsaturated ketone moiety and/or α,β-saturated ketone structure were synthesized from curcumin via alkylation at the central carbon and the phenolic hydroxy groups, and hydrogenation of α,β-unsaturated ketone moiety. The antiproliferative activities were tested in five human solid tumor cell lines in vitro. Most of the compounds exhibited increased antiproliferative activities comparing with that of curcumin. Structure-activity relationship (SAR) analysis revealed that the α,β-unsaturated ketone structure was not required for antiproliferative activity of these curcumin analogues. Among these compounds, 1,7-bis(3-methoxy-4-(3-(4-methylpiperazinyl-1-yl)propoxy)phenyl)-4,4-dibenzylheptane-3,5-dione (16f) was the most effective one with IC50 value below 1 µM, which was 9- to 81-fold more potent than curcumin.

ChemInform Abstract: β‐Cyclodextrin‐Mediated Acetic Acid Catalyzed Diastereoselective Mannich Reaction in Water.

AbstractThe title reaction occurs in a syn‐selective fashion when propiophenone(III) is utilized as the ketone moiety, and in an anti selective manner when cyclohexanone (III) is utilized.

Stable cycling of lithium sulfide cathodes through strong affinity with a bifunctional binder

A manufacturing method of a battery electrode includes: (1) mixing Li2S particles with a binder to form a slurry, the binder including at least one of: (a) an ester moiety, (b) an amide moiety, (c) a ketone moiety, (d) an imine moiety, (e) an ether moiety, and (f) a nitrile moiety; and (2) disposing the slurry on a current collector.

Design of new Type I and Type II photoinitiators possessing highly coupled pyrene–ketone moieties

New Type I and Type II photoinitiators based on 2,2-dimethoxy-2-phenylacetophenone (DMPA), benzophenone (BP) and thioxanthone (TX) linked to a pyrene (Py) moiety (Py_DMPA, Py_BP, Py_TX) are proposed here for the free radical polymerization of acrylates and the cationic polymerization of epoxides and vinylethers under a Xe–Hg lamp, laser diode at 405 nm or a halogen lamp. Excellent polymerization profiles using Py_DMPA and Py_BP are obtained, i.e. better than those recorded with the reference compounds (DMPA and BP). Specifically, Py_DMPA and Py_BP absorb in the near UV-visible range (360–420 nm range; absorption red-shift ∼15 nm), exhibit huge e values (up to a 90 fold increase) and high photochemical reactivity. The mechanisms analyzed by electron spin resonance, steady state photolysis, fluorescence and laser flash photolysis experiments are discussed for the different initiating systems.

Symmetric and unsymmetric 3,3′-linked bispyrroles via ring-enlargement reactions of furan-derived donor–acceptor cyclopropanes

A short and concise sequence for the synthesis of symmetrically and unsymmetrically substituted 3,3'-linked bispyrroles is described. Furan as a starting material is subjected to a twofold cyclopropanation by a diazo ester. Conversion of the ester functionalities to the respective ketones is achieved via Weinreb amide formation and the attack of a Grignard reagent. In the presence of amines the ketone moieties form imines that rearrange by ring-enlargement of the three-membered to the five-membered rings. In situ generated dihydropyrrole moieties eliminate water and afford aromatic pyrrole units. Unsymmetric bispyrroles are obtained by using different cyclopropanating agents or varying Grignard reagents for ketone formation before the addition of amines initiates the cascade to the respective bispyrroles.

Genetic Incorporation of Twelve meta-Substituted Phenylalanine Derivatives Using a Single Pyrrolysyl-tRNA Synthetase Mutant

When coexpressed with its cognate amber suppressing tRNACUAPyl(CUA), a pyrrolysyltRNA synthetase mutant N346A/C348A is able to genetically incorporate 12 meta-substituted phenylalanine derivatives into proteins site-specifically at amber mutation sites in Escherichia coli. These genetically encoded noncanonical amino acids resemble phenylalanine in size and contain diverse bioorthogonal functional groups such as halide, trifluoromethyl, nitrile, nitro,ketone, alkyne, and azide moieties. The genetic installation of these functional groups in proteins provides multiple ways to site-selectively label proteins with biophysical and biochemical probes for their functional investigations. We demonstrate that a genetically incorporated trifluoromethyl group can be used as a sensitive 19F NMR probe to study protein folding/unfolding, and that genetically incorporated reactive functional groups such as ketone,alkyne, and azide moieties can be applied to site-specifically label proteins with fluorescent probes. This critical discovery allows the synthesis of proteins with diverse bioorthogonal functional groups for a variety of basic studies and biotechnology development using a single recombinant expression system.

Copper(I)-Catalyzed Enantioselective Incorporation of Ketones to Cyclic Hemiaminals for the Synthesis of Versatile Alkaloid Precursors

A general catalytic enantioselective method that can produce five-, six-, and seven-membered N-heterocycles possessing various ketone moieties starting from stable and easily available cyclic hemiaminals and ketones was developed. The method involves three successive steps in one pot (aldol addition, dehydration, and enantioselective intramolecular aza-Michael reaction), all of which are promoted by a chiral copper(I)-conjugated Brønsted base catalyst. This method is useful for rapid access to versatile chiral building blocks for the synthesis of drug-lead alkaloids.

β-Cyclodextrin-Mediated Acetic Acid Catalyzed Diastereoselective Mannich Reaction in Water

A highly efficient diastereoselective Mannich reaction has been carried out in water using a catalytic amount of β-cyclodextrin as a chiral host in the presence of acetic acid to give the corresponding β-aminoketones (Mannich bases) with good yield (up to 98%) and excellent diastereomeric excess (up to >99%). This ­Bronsted acid–chiral cyclodextrin composite catalyzed reaction proceeds in a syn-selective manner with 98:2 syn/anti selectivity when propiophenone is used as the ketone moiety and in an anti-­selective manner with 100:0 (anti/syn) selectivity when cyclohexanone is used.