Ketone Oxime Research Articles

Design, synthesis, and biological activities of novel azole-bonded β-hydroxypropyl oxime O-ethers.

The synthesis and biological effects of 15 novel azole-bonded β-hydroxypropyl oxime O-ethers have been described. In this synthesis, the oximation of aromatic ketones followed by an O-alkylation reaction with epichlorohydrin and/or epibromohydrin led to the corresponding O-oxime ether adducts. Subsequently, the attained O-oxime ether adducts were used to synthesize the target molecules after treating them with the appropriate azole derivatives. The in vitro antifungal and antibacterial activities of title compounds were obtained against several pathogenic fungi, Gram-positive and/or Gram-negative bacteria. Benzophenone O-2-hydroxy-3-(2-phenyl-1 H-imidazol-1-yl) propyl oxime and 9H-fluoren-9-one O-2-hydroxy-3-(2-phenyl-1 H-imidazol-1-yl)propyl oxime proved to have considerable antifungal activity against Candida albicans, Candida krusei, Aspergillus niger, and Trichophyton rubrum. These two compounds demonstrated comparable antifungal activity to clotrimazole and fluconazole (standard drugs). All compounds were also tested against Escherichia coli and Staphylococcus aureus as Gram-negative and Gram-positive bacteria, respectively, and their activities were compared to gentamycin and ampicillin (reference drugs). In general, marginal antibacterial activity against tested bacteria was observed for the title compounds. A molecular docking study is also discussed for the two most potent compounds against fungi. The docking study reveals a considerable interaction between the two most potent compounds and the active site of Mycobacterium P450DM. Moreover, these two compounds are much strongly bound to the active site of Mycobacterium P450DM compared to fluconazole.

Methyl ketone oxime esters as nucleophilic coupling partners in Pd-catalyzed C-H alkylation and application in the synthesis of isoquinolines.

Methyl ketone oxime esters have been found to be excellent coupling partners for C(sp(2))-C(sp(3)) bond formation via Pd-catalyzed aromatic C-H activation. This transformation forms the basis of an approach to regioselectively synthesize substituted isoquinolines via coupling with aryloxime esters. Our mechanistic studies suggested that the reaction proceeded through Pd(II)-catalyzed aromatic C-H activation, tautomerization, and a 1,3-shift of the palladacycle-ligated methyl ketone oxime ester to enable the C-C bond formation by reductive elimination, and intramolecular condensation of an imido-Pd(II) intermediate to form the heterocycle. The aryloxime group not only was used as a directing group for Pd-catalyzed aromatic C-H activation but also functioned as an internal oxidant to allow the reaction to be redox-neutral. Our study illuminated the scope and limitations of this C-H alkylation process, which may serve as the point of departure for developing other C-H functionalization reactions using oxime esters and potentially other carbonyl derivatives as the nucleophilic coupling partners.

Highly efficient synthesis of methyl ethyl ketone oxime through ammoximation over Ti-MOR catalyst

The liquid-phase ammoximation of methyl ethyl ketone(MEK) to methyl ethyl ketone oxime(MEKO) with ammonia and hydrogen peroxide was conducted over MOR-type titanosilicate(Ti-MOR),which was prepared from highly dealuminated mordenite and TiCl4 vapor by a secondary method of gas-solid phase reaction.The effects of reaction parameters on this reaction were studied systematically in a bath-type reactor.Based on the optimized reaction conditions,Ti-MOR was further employed as the catalyst for the ammoximation of MEK to MEKO in a continuous slurry reactor.This catalyst exhibited good catalytic activity and excellent MEKO selectivity in comparison to TS-1.Moreover,in terms of ketone conversion,oxime selectivity,coke resistance,and lifetime,Ti-MOR possessed the same advantages as the Ti-MWW catalyst prepared by structural rearrangement.

Synthesis and catalytic ammoxidation performance of hierarchical TS-1 prepared by steam-assisted dry gel conversion method: the effect of TPAOH amount

The hierarchical titanium silicalite-1 (TS-1) was synthesized by the steam-assisted dry gel conversion method in one step and characterized by XRD, SEM, N2 adsorption/desorption, UV–Vis, FT-IR, and Raman spectroscopies. And its catalytic activity was tested for ammoxidation of methyl ethyl ketone with hydrogen peroxide as oxidant. The results show that the amount of tetrapropylammonium hydroxide (TPAOH) as template has a major influence on the physicochemical and catalytic properties of the hierarchical TS-1 prepared. When lower amount of TPAOH (TPAOH/SiO2 = 0.08 mol) was used, hierarchical TS-1 can be successfully synthesized. With an increase in TPAOH amount in synthesis solution, the crystal size of TS-1 is decreased and mesoporous surface area is increased; if the excess template was used in the synthesis of TS-1, more extra-framework Ti would be formed in the TS-1 samples prepared. The hierarchical TS-1 exhibits higher catalytic activity than TS-1 prepared hydrothermally for ammoxidation of methyl ethyl ketone. Using hierarchical TS-1 synthesized under TPAOH/SiO2 = 0.18 as the catalyst, which has more tetrahedrally coordinated Ti species in the TS-1 framework, 94.2 % conversion of reactant and 100 % selectivity to methyl ethyl ketone oxime can be obtained after 2 h of reaction at 70 °C.

ChemInform Abstract: Highly Selective and Efficient Lewis Acid—Base Catalysts Based on Lanthanide‐Containing Polyoxometalates for Oximation of Aldehydes and Ketones.

AbstractThis easily prepared catalyst can be reused over six times without significant loss of activity.

Use of the oxime–oximato binding mode to stabilise mixed valence copper iodide polymer networks using dipyridyl ketone oxime ligands

Coordination polymers formed from copper iodide and four isomeric dipyridyl ketone oxime ligands showed the importance the oxime–oximato bridge on the formation of mixed valence Cu(i)/Cu(ii) polymers.

Conversion of Pyridine to Imidazo[1,2-a]pyridines by Copper-Catalyzed Aerobic Dehydrogenative Cyclization with Oxime Esters

A rapid and environmentally friendly conversion of pyridine to imidazo[1,2-a]pyridines has been developed via copper-catalyzed aerobic dehydrogenative cyclization with ketone oxime esters.

Dimeric and Tetrameric Supramolecular Aggregates of Single-Molecule Magnets via Carboxylate Substitution

[Mn3]2 and [Mn3]4 supramolecular aggregates of weakly exchange-coupled Mn(III)3 single-molecule magnets (SMMs) with S = 6 have been prepared by carboxylate substitution on [Mn3O(O2CMe)3(mpko)3](+) [mpkoH = methyl(pyridine-2-yl) ketone oxime)] with the dicarboxylic acids α-truxillic acid and fumaric acid, respectively. The method opens up a new approach to Mn3 SMM aggregates of various size and topology.

Interplay of ortho- with spiro-cyclisation during iminyl radical closures onto arenes and heteroarenes.

Sensitised photolyses of ethoxycarbonyl oximes of aromatic and heteroaromatic ketones yielded iminyl radicals, which were characterised by EPR spectroscopy. Iminyls with suitably placed arene or heteroarene acceptors underwent cyclisations yielding phenanthridine-type products from ortho-additions. For benzofuran and benzothiophene acceptors, spiro-cyclisation predominated at low temperatures, but thermodynamic control ensured ortho-products, benzofuro- or benzothieno-isoquinolines, formed at higher temperatures. Estimates by steady-state kinetic EPR established that iminyl radical cyclisations onto aromatics took place about an order of magnitude more slowly than prototypical C-centred radicals. The cyclisation energetics were investigated by DFT computations, which gave insights into factors influencing the two cyclisation modes.

A Development of Rapid, Practical and Selective Process for Preparation of Z-Oximes

Oximes are important functional groups in organic chemistry due to their synthetic utility as protecting groups for carbonyl groups and their ability to form other functionalities, 1�4 and their biological activity. 5 Oximes are commonly prepared by condensing aldehydes and ketones with hydroxylamines. These reactions do not always go to completion and reaction times can be long, and therefore there has been interest in more convenient and efficient methods. To avoid the typical disadvantage, conversion of aldehydes and ketones to the corresponding oximes was accomplished by using various catalysts such as organic acid/bases, 1,2,6 AcONa, alumina, 7 TiO2/SO4 2� , 2 silica gel, 8 Oxone®, 9 NaOH, 10 basic ionic liquid 1-butyl-3-methylimidazolium hydroxide, 11 polyoxometalates, 12 Na2SO4, 13 and CuSO4/K2CO3 14 under the solvent, the solvent-free or the microwave conditions. These are one and more drowbacks such as long reaction time, use of catalysts, inconvenients due to solid-sate reaction, low yields and limitaion of some carbonyl compounds. On the other hand, H. Sharghi, et al., 14 reported the catalysis of the stereoselectivity of CuSO4 and K2CO3 in the oximation of aldehydes and ketones under solvent-free conditions. Although this method show high selectivity, it is inconvenient for the large scale experiments and the industrial process due to the solvent-free condition. Therefore, we attempted to develop a more convenient and efficient solution method. According to the literatures, 15 treatment of potassium carbonate with methanol generates slightly the potassium methoxide, which may be useful for forming the free NH2OH from its salts. We describe the oximation of aldehyde and ketone using NH2OH·HCl/K2CO3 in methanol solvent.

ChemInform Abstract: O,O‐Diethyl Dithiophosphoric Acid Mediated Direct Synthesis of Thioamides from Aldehydes and Ketones.

AbstractThe simple one‐pot approach proceeds via oximation of ketones and aromatic aldehydes followed by deoxygenative thioamidation.

Esters of isoxazole- and isothiazolecarboxylic acids and oximes of β-isatin, isoxazole- and ferrocene-containing ketones and carborane alcohols

Oximes of β-isatin, isoxazole- and ferrocene-containing ketones, o- and m-carborane alcohols react with isoxazol- and isothiazolecarboxylic acid chlorides in the presence of triethylamine to afford the corresponding esters.

A novel UV-MALDI-MS analytical approach for determination of halogenated phenyl-containing pesticides

The paper highlighted the capability of the UV-MALDI mass spectrometry, employing the Orbitrap analyzer for solid-state assay of halogenated phenyl–pesticides in mixtures. It is successfully applied for the analysis of eighteen (1)–(18) molecular objects of Fenarimol (1) type and their condensation products (P5)–(P12). The full method and technique validation is performed using the dried droplet sample preparation technique on embedded analytes in novel organic matrix crystals of N-(1H-benzoimidazol-2-yl)-guanidine (M4) and (E)-phenyl-2-pyridyl ketone oxime (M5), resulting to successful ionization of the analytes. Since the sampling technique in the UV-MALDI method is a key step in the overall process impacting significantly the metrology through the reproducibility of the data, the crystallization of M4, M5 and matrix–analyte in situ morphology of the samples is controlled by single crystal X-ray diffraction. The achieved promising metrology of LODs, of 0.46ngkg−1 (1.53ngkg−1 LOQs), is several orders of magnitude lower than the reported ecotoxicological effect values of studied pesticides. It is confirmed by the partial validated protocol based on ESI-MS. Inasmuch that LC-MS/MS is a method of choice for foodstuffs monitoring of organic contaminations, due to its routine quantitative analytical procedures, it is often characterized with the difficulties of the chromatographic separation of the closely structured analytes at a large scale of experimental conditions, complex multi-step sampling pretreatments, which inevitably alert the variables through the systematic and random errors. In this respect, notwithstanding the complex quantitative UV-MALDI-Orbitrap-MS procedure, conceptually different from the LC-MS/MS one, its high resolving power, capability for achieving meaningful analytical qualitative, quantitative and structural information of low-molecular weight analytes, its instrumental and sampling operation flexibility, applicable for a large scale of foodstuff matrices, and operating at the analyte concentrations of up to fgg−1 make UV-MALDI-Orbitrap-MS a perspective method of choice for an extensive implementation in the foodstuffs monitoring practice for control of the most essential task related to the assessment of the human health risks from environmental and foodstuff contaminations.

Triflate anion and ligand influences in silver(i) coordination polymers of four isomeric dipyridyl ketone oximes

The synthesis and X-ray characterisation of four isomeric dipyridyl ketone oxime ligands, 4,4′-dipyridyl ketone oxime, L44, 3,3′-dipyridyl ketone oxime, L33, 2,4-dipyridyl ketone oxime, L24 and 2,3-dipyridyl ketone oxime, L23 is described. X-ray structural characterisation of the precursor ketones 3,3′-dipyridyl ketone, L1, and 2,4-dipyridyl ketone, L2, is also reported for comparison. Four AgCF3SO3 complexes of the dipyridyl ketone oxime ligands were prepared and structurally characterised, [Ag(L44)2](CF3SO3), 1, {[AgL33](CF3SO3)}∞, 2, [AgL24(CF3SO3)]∞, 3, and [Ag2L23(CF3SO3)2]∞, 4. The structural role of the CF3SO3− anion in the formation of Ag(I) coordination polymer networks, together with the effect of the varying pyridyl substitution patterns of L44, L33, L24 and L23 was investigated. In 1 the CF3SO3− anion was unbound and disordered. It was encapsulated in the channels of a honeycomb 3D H-bonded structure. In 2 the CF3SO3− anion remained unbound, being encapsulated within the centre of a helical polymer chain. In 3 the CF3SO3− anion was weakly bound to the Ag(I) ion and as such decorated the side of a bowed 1-D chain. The two different CF3SO3− anions in 4 adopted a range of binding modes from monodentate, bis-monodentate to tris-monodentate with the Ag(I) ions and gave rise to the formation of an unusual CF3SO3− bridged 2-D network.

Synthesis of Sabina δ-Lactones and Sabina δ-Lactams from (+)-Sabinene

Two sabina δ-lactones (3 and 4) were obtained in a two-step synthesis from (+)-sabinene (1). The oxidation of (+)-sabinene (1) with potassium permanganate and sodium periodate to (–)-sabina ketone (2) was the first step. In the second step, the ketone obtained was subjected to chemical and microbial Baeyer–Villiger oxidation. Chemical Baeyer–Villiger oxidation of this ketone afforded two δ-lactones 3 and 4 whereas microbial Baeyer–Villiger oxidation afforded only ‘abnormal’ δ-lactone 4. (–)-Sabina ketone was also the starting material for the synthesis of new δ-lactams (7 and 8). They were obtained by Beckmann rearrangement of sabina ketone oximes 5a and 5b. An attempt to separate (–)-sabina ketone oximes 5a and 5b is also presented.

Synthesis of ketoximes via a solvent-assisted and robust mechanochemical pathway

A versatile and robust mechanochemical route to ketone–oxime conversions has been established for a broad range of ketones via a simple mortar–pestle grinding method. The relative reactivity of aldehydes vs. ketones under these conditions has also been explored, along with an examination of the possible connection between reactivity and electronic substituent effects.

Nickel(II) complexes with methyl(2-pyridyl)ketone oxime: Synthesis, crystal structures and DFT calculations

The synthesis and structural characterization of the three novel nickel(II) complexes [Ni(OOCPh)2(mpkoH)2] (1), [Ni(NO3)2(mpkoH)2] (2) and [Ni(mpkoH)3](NO3)2⋅½H2O (3⋅½H2O), with mpkoH=methyl(2-pyridyl)ketone oxime is reported. Geometry optimization and population analyses were performed by means of DFT calculations for the previously mentioned compounds as well as for [NiCl2(mpkoH)2] (4). Electronic UV–vis spectra were also simulated in the TD-DFT framework to assign the origin of the absorption bands and in doing so, to have a clear picture of the absorptive features of the coordination compounds under investigation.

O,O-Diethyl dithiophosphoric acid mediated direct synthesis of thioamides from aldehydes and ketones

A general and convenient method for a one-pot conversion of aldehydes and ketones into thioamides has been developed. The protocol involves oximation of aldehydes and ketones followed by deoxygenative thioamidation of oximes with O,O-diethyl dithiophosphoric acid which acts as an acid as well a source of sulfur. The method is operationally simple, high yielding, and also applicable to the conversion of amides and nitriles into the corresponding thioamides.

ChemInform Abstract: Synthesis of Isoquinolines and Heterocycle‐Fused Pyridines via Three‐Component Cascade Reaction of Aryl Ketones, Hydroxylamine, and Alkynes.

An efficient one-pot synthesis of isoquinolines and heterocycle-fused pyridines by three-component reaction of aryl ketones, hydroxylamine, and alkynes is developed. The reaction involves condensation of aryl ketones and hydroxylamine, rhodium(III)-catalyzed C–H bond activation of the in situ generated aryl ketone oximes, and cyclization with internal alkynes. This protocol enables rapid assembly of multisubstituted isoquinolines as well as γ-carbolines, furo[2,3-c]pyridines, thieno[2,3-c]pyridines, and benzofuro[2,3-c]pyridines from readily available substrates.

Highly Selective and Efficient Lewis Acid–Base Catalysts Based on Lanthanide‐Containing Polyoxometalates for Oximation of Aldehydes and Ketones

AbstractTwo lanthanide‐containing polyoxometalates (POMs) have been developed as Lewis acid–base catalysts for highly selective and efficient oximation of various aldehydes and ketones under mild conditions.