Saturated Ketones Research Articles

Copper(i)-catalyzed N-H olefination of sulfonamides for N-sulfonyl enaminone synthesis.

This communication reports copper-catalyzed N-H olefination of sulfonamides for enaminone synthesis using saturated ketones as olefin sources. With TEMPO derivatives and O2 as oxidants, this method provided an efficient way to produce various enaminones in good yields. Mechanistic studies helped figure out the stable intermediates and develop novel methodologies for the difunctionalization of saturated ketones.

Copper Catalysis for Nicotinate Synthesis through β‐Alkenylation/Cyclization of Saturated Ketones with β‐Enamino Esters

AbstractThe first example of a Cu‐catalyzed and 4‐OH‐TEMPO mediated intermolecular [3+3] annulation of saturated ketones with β‐enamino esters is reported herein, which was successfully used for the synthesis of versatile nicotinates through sequential β‐C(sp3)‐H bond alkenylation, enamine‐carbonyl condensation and aromatization. This protocol tolerates a variety of functional groups, thereby providing a practical and efficient method for the fabrication of 5H‐chromeno[4,3‐b]pyridin‐5‐one skeletons.magnified image

Two efficient pathways for the synthesis of aryl ketones catalyzed by phosphorus-free palladium catalysts

Allylic alcohols, 1-buten-3-ol, 1-penten-3-ol and 1-octen-3-ol, reacted with aryl iodides (iodotoluene, 4-iodotoluene, 4-iodophenol and 4-iodanisole) under Heck reaction conditions to form corresponding saturated aryl ketones in one step. The same products were obtained in a two-step tandem reaction consisted of the Heck coupling of allylic alcohols with aryl iodides, followed by hydrogenation. Reactions were catalyzed by phosphorus-free palladium precursors modified with the menthol-substituted imidazolium chlorides. Formation of crystalline palladium nanoparticles, of the diameter up to 65nm, in the reaction mixture was evidenced by TEM.

Influence of mineral substances on the synthesis of volatile organic compounds by Pleurotus ostreatus in the process of solid phase cultivation

Mineral substances play an important role in ensuring high-grade growth and high organoleptic quality of the fruit bodies of basidiomycetes. In the process of solid-phase cultivation of the mushroom Pleurotus ostreatus (Jacq.: Fr.) Kumm. the lignocellulosic substrates were enriched with mineral additives of calcium, iron and selenium. Their influence on the synthesis of volatile aroma compounds was investigated by the methods of sensory profile analysis and ultraviolet spectroscopy. Mineral additives in the form of CaCl2, FeSO2•7H2O and Na2SeO3 salts were added to the substrate (sunflower husk, barley straw) before sterilization in concentrations that correspond to the physiological needs of the mushrooms. When carrying out a sensory profile analysis of dried fruit bodies, the following attributes of the flavor were determined: mushroom, woody, sweet, herbaceous, fish, meat, floral, earthy, acidic, putrescent. The conducted profile analysis showed an unequal dependence of the effect of mineral additives for each of the P. ostreatus strains. For IBK-549 and IBK-1535, an increase in the intensity of mushroom notes of aroma was observed with the addition of calcium and selenium to the husks, and for IBK-551, this was observed with the addition of iron and selenium to both substrates. The volatile aroma compounds were extracted with hexane at boiling point for 30 minutes. Absorption spectra were recorded in the wavelength range 200–330 nm. The examined extracts had light absorption maxima at 200–210 and 260–300 nm, which is typical for solutions of unsaturated compounds that have non-conjugated double bonds, saturated and unsaturated aldehydes and ketones. Additions of iron to the substrates increased the intensity of light absorption in comparison with the control. Additions of selenium selectively influenced different strains, and calcium ions did not significantly affect the change in the intensity of light absorption, and therefore the synthesis of volatile compounds by mushrooms. The level of synthesis of aroma-forming substances was higher when cultivating fungi on sunflower husks than on barley straw. This was confirmed both by the obtained aroma profiles and by the recorded absorption spectra of all examined strains. The study showed the possibility of influencing the organoleptic qualities of P. ostreatus fruiting bodies during solid-phase cultivation by supplementing the composition of lignocellulosic substrates with various mineral additives.

Synthesis of Functionalized Pyridines via Cu(II)-Catalyzed One-Pot Cascade Reactions of Inactivated Saturated Ketones with Electron-Deficient Enamines.

In this paper, a novel and efficient synthesis of 3-acylpyridines and pyridine-3-carboxylates through the oxidative one-pot sequential reactions of inactivated saturated ketones with electron-deficient enamines is presented. Mechanistically, the formation of the title compounds involves the in situ formation of an enone intermediate through an oxidative dehydrogenation of the saturated ketone substrate, followed by its [3+3] annulation with β-enaminone or β-enaminoester via a cascade process, including Michael addition, aldol type condensation, and oxidative aromatization.

Modifying electron transfer between photoredox and organocatalytic units via framework interpenetration for \u03b2-carbonyl functionalization

Modifying electron transfer pathways is essential to controlling the regioselectivity of heterogeneous photochemical transformations relevant to saturated carbonyls, due to fixed catalytic sites. Here we show that the interpenetration of metal–organic frameworks that contain both photoredox and asymmetric catalytic units can adjust the separations and electron transfer process between them. The enforced close proximity between two active sites via framework interpenetration accelerates the electron transfer between the oxidized photosensitizer and enamine intermediate, enabling the generation of 5πe− β-enaminyl radicals before the intermediates couple with other active species, achieving β-functionalized carbonyl products. The enriched benzoate and iminium groups in the catalysts provide a suitable Lewis-acid/base environment to stabilize the active radicals, allowing the protocol described to advance the β-functionalization of saturated cyclic ketones with aryl ketones to deliver γ-hydroxyketone motifs. The homochiral environment of the pores within the recyclable frameworks provides additional spatial constraints to enhance the regioselectivity and enantioselectivity.

Base-promoted isomerization of CF3-containing allylic alcohols to the corresponding saturated ketones under metal-free conditions.

Following to the computational expectation, our previously reported intriguing 1,3-proton shift of 4,4,4-trifluorobut-2-yn-1-ols was successfully extended to the 4,4,4-trifluorobut-2-en-1-ol system under metal-free conditions to afford the corresponding saturated ketones in high to excellent chemical yields using such a convenient and easy-to-handle base as DBU at the toluene refluxing temperature, and utilization of the corresponding optically active substrates unambiguously demonstrated that this transformation proceeded in a highly stereoselective fashion.

Synthesis of 4-Acylpyrazoles from Saturated Ketones and Hydrazones Featured with Multiple C(sp3)-H Bond Functionalization and C-C Bond Cleavage and Reorganization.

In this paper, an efficient and convenient one-pot synthesis of diversely substituted 4-acylpyrazole derivatives via copper-catalyzed one-pot cascade reactions of saturated ketones with hydrazones is reported. Mechanistically, the formation of the title compounds involves the in situ formation of an enone intermediate through the dehydrogenation of a saturated ketone and the [2 + 3] cyclization of the enone with hydrazone followed by an aromatization-driven C-C bond cleavage and reorganization. To our knowledge, this is the first example in which the biologically and pharmaceutically important yet otherwise difficult-to-obtain 4-acylpyrazole derivatives are directly prepared from saturated ketones and hydrazones featured with multiple aliphatic C-H bond functionalization and C-C bond cleavage and reorganization. Compared with literature methods, this novel process has advantages such as simple and economical starting materials, a sustainable oxidant, excellent regioselectivity, and good efficiency.

Chemical reactions in the pyrolysis of brown grease

Brown grease breaks down into a mixture of alkanes and alkenes at temperatures above 300°C without addition of hydrogen or an external catalyst. To better understand the reactions in this process, pyrolysis experiments were performed on palmitic and oleic acids as model systems for the saturated and unsaturated fatty acids in brown grease, respectively. Iron (III) sulfate was used in half of the experiments, as Fe(III) is normally found in brown grease; and the other experiments were performed without iron as controls. In the presence of Fe(III), palmitic acid forms a series of aliphatic hydrocarbons and some palmitone byproduct, while the iron-free control experiment yielded larger quantities of palmitone, up to more than 50%. However, regardless of Fe(III), oleic acid broke down into shorter saturated fatty acids, hydrocarbons, alcohols, aldehydes, esters, and ketones, according to known thermal reactions of unsaturated fatty acids. The product fatty acids then reacted in a manner similar to palmitic acid. The major ketone and alcohol byproducts were also examined for reactions ultimately leading to the desired products.

Nickel-catalyzed reduction of ketones with water and triethylsilane

The acetophenone (1a) reduction using catalytically active nickel complexes and water is an efficient and sustainable method to access a new methodology of transfer hydrogenation of ketones. When triethylsilane (Et3SiH) was used as sacrificial agent to promote the transfer hydrogenation from water, 1-phenylethanol (2a) was obtained in excellent yield along with silanol (Et3SiOH) as the reaction’s driving force. Deuterium labeling studies were made using Et3SiD or D2O and these studies showed that both compounds participate as hydride sources for the ketone reduction. A scope of substrates was assessed, including a variety of mono/diketones, and α,β-unsaturated ketones, to yield the corresponding secondary alcohols and saturated ketones. Additionally, asymmetric transfer hydrogenation of mono-ketones was studied for the mixture of nickel/(bisphosphine or phospholane) as catalyst precursor, using H2O/Et3SiO system and ethanol as hydrogen sources.

Stereo-complementary bioreduction of saturated N -heterocyclic ketones

Abstract The asymmetric bioreduction of several saturated N-heterocyclic ketones is demonstrated in a stereo-complementary fashion using the ketoreductases READH and ChKRED20 for the production of (S)- and (R)-alcohols, respectively. The reaction accepts substrates with a five-, six- or seven-membered ring, and exhibits excellent stereoselectivity when using 2-propanol as both the ultimate reducing agent and cosolvent, achieve >99% ee in the majority of cases for both enantiomers.

English

Rauwolfia vomitoria Aftzel belong to the family of Apocynacea with a common name serpent wood and Igbo name as akanta. It is used traditionally to treat hypertension and rheumatoid arthritis. The present study deals with GC-MS determination and FT-IR analysis of methanolic root extract of the named plant. Exactly thirty phytochemical constituents have been identified by comparing the chromatogram peek values of unknown compounds with entries in NIST database. The major bioactive compounds were 2-Formyl-9-[b-d-ribofuranosyl]hypoxanthine (8.63%), 5-Cyclopropylcarbonyloxypenta-decane (5.58%), 1,2,5-Oxadiazol-3-carboxamide-4,4’-azobis-2,2’-dioxide (4.47%), 1-(5-Bicylco[2.2.1]heptyl)ethylamine (3.66%), 1-Adamantanemethylamine,a-methyl- (2.22%), Diphenylephrine (1.26%), Imidazole,2-amino-5-[(2-carboxy)vinyl]- (0.85%), Spiro[androst-5-ene-17,1’-Cyclobutan]-2’-one,3-hydroxy-,(3b,17b)- (0.82, and Cyclohexan-1,4,55-triol-3-one-1-carboxylic acid (0.65%). The FTIR spectrum confirmed the presence of alkyl halides, alcohols, phenols, secondary alcohols, tertiary alcohols, aromatic ethers, aldehydes, ketones, aliphatic nitro compound, aromatic organophosphorus compounds, aromatic compounds, carboxylic acid derivatives, alkenes, saturated ketones, and alkanes. Hence, this study offers bases of employing R. vomitoria as herbal alternative for the treatment of various diseases. Key words: Fourier transform infrared spectrometry (FTIR), gas chromatography-mass spectrometry (GC-MS), phytochemical, Rauwolfia vomitoria Aftzel.

Chemoselective C(α)–C(β) bond cleavage of saturated aryl ketones with amines leading to α-ketoamides: a copper-catalyzed aerobic oxidation process with air

An unprecedented chemoselective C(α)–C(β) bond cleavage of simple saturated aryl ketones with amines leading to α-ketoamidesvia a copper-catalyzed aerobic oxidation process with air has been disclosed.

α,β-Functionalization of saturated ketones with anthranils via Cu-catalyzed sequential dehydrogenation/aza-Michael addition/annulation cascade reactions in one-pot

An efficient method to access functionalized quinolines from the readily available saturated ketones and anthranils has been explored. This one-pot cascade reaction involves the in situ generation of α,β-unsaturated ketones by the copper catalysed dehydrogenation of saturated ketones followed by the aza-Michael addition of anthranils and subsequent annulation.

Flg22‐triggered oxylipin production in Pyropia haitanensis

SUMMARYThis study provides evidence that flg22, the most conserved 22‐amino acid peptide in the N‐terminal part of bacterial flagellin can trigger the defense responses of Pyropia haitanensis (Bangiales, Rhodophyta). The defense responses are a chain of events including release of H2O2 and free unsaturated fatty acids C20:4, consumption of C18:3, and the chemical or enzymatic oxidation of both C20 and C18 polyunsaturated fatty acids. Oxidized C20 and C18 fatty acids lead to the production of corresponding hydroperoxy and hydroxylated derivatives, such as 9‐hydroperoxy octadecadienoic acid, 8‐hydroperoxy eicosapentaenoic acid, and 8‐hydroxyl eicosapentaenoic acid, which could be further oxidatively metabolized to yield saturated aldehydes and ketone. Changes of three typical hormones jasmonate, methyl jasmonate, and salicylic acid were observed. Contrary to the increase of jasmonate and methyl jasmonate, salicylic acid was decreased. The expression of key enzymes of oxylipin pathway PhLOX and PhLOX2 were upregulated. However, some defense and antioxidant related genes including PhHsp 70, Phsod , and PhRboh were downregulated markedly at the early stage of flg22 challenge. Overall, our results imply that red algae have evolved a similar defense response and may share the conservative‐recognizing receptor for flg22 as in higher plants.

Base free transfer hydrogenation using a covalent triazine framework based catalyst

Isomerisation of allylic alcohols to saturated ketones can be efficiently catalysed by a heterogeneous molecular system resulting from IrIIICp* anchoring to a covalent triazine framework.

Synthesis of 3-acylquinolines through Cu-catalyzed double C(sp3)–H bond functionalization of saturated ketones

A novel synthesis of 3-acylquinolines through Cu-catalyzed one-pot reactions of 2-aminoaryl aldehydes/ketones with inactivated ketones featured with double C(sp3)–H bond functionalization is presented.

Metal-free nitroxyl radical-mediated β-C(sp3)-H amination of saturated ketones with heteroaryl halides: multiple roles of TEMPO.

The first metal-free nitroxyl-radical-mediated β-amination of saturated ketones by using heteroaryl halides as amide precursors has been developed. This reaction proceeds through a cascade α-aminoxylation/Cope-like elimination/aza-Michael addition sequence to afford β-amino ketone derivatives with excellent yields. TEMPO plays multiple roles in the current β-amination process, including those of an oxidant, an α-aminoxylation reagent, a β-hydrogen acceptor, an in situ base, and an oxygen source.

Organic compound-mineral interactions: Using flash pyrolysis to monitor the adsorption of fatty acids on calcite

Fatty acids are near ubiquitous organic compounds in living organisms in the Earth’s biosphere. Following death of an organism in the marine environment its fatty acids may survive descent to the sea bed where they can be juxtaposed with minerals. The aim of this study was to investigate the interaction of fatty acids with the common marine mineral calcite. Adsorption of tetradecanoic acid (C14) on calcite results in a sigmoidal or “s” isotherm. Flash pyrolysis experiments were conducted on samples of fatty acid adsorbed onto calcite and were compared with similar experiments on pure fatty acid and on salts of a fatty acid. Flash pyrolysis of pure tetradecanoic acid generated unsaturated and saturated hydrocarbons and a series of unsaturated and saturated low molecular weight fatty acids. Flash pyrolysis of free tetradecanoic acid salt produced saturated and unsaturated hydrocarbons, an aldehyde and a homologous series of saturated and unsaturated ketones, one of which was a symmetrical mid chain ketone (14-heptacosanone). Flash pyrolysis data from adsorbed tetradecanoic acid samples suggested that adsorption is analogous to the formation of the calcium salt of tetradecanoic acid. A key characteristic of the flash pyrolysis products of adsorbed fatty acids and fatty acid salts was the production of ketones with higher molecular weights than the starting fatty acids. Ketonisation was not observed from the flash pyrolysis of pure acid which implied the catalytic significance of the calcite mineral surface. The abundance of hydrocarbons relative to ketones in the pyrolysates negatively correlated with the proportion of fatty acids adsorbed to the surface of calcite. The ability to use flash pyrolysis to diagnose the nature of fatty acid interactions with mineral surfaces provides a valuable tool for monitoring the fate of these important lipids at the Earth’s surface as they pass into the geosphere and are subjected to diagenetic processes.

ChemInform Abstract: Simple Primary Amino Amide Organocatalyst for Enantioselective Aldol Reactions of Isatins with Ketones.

AbstractAmong a number of amino acid amide‐derived organocatalysts, L‐tert‐leucine derivative TLA features best efficiency in terms of yield, dia‐ and enantiostereoselectivities in the title reaction, in particular, when 6‐membered saturated (hetero)cyclic ketones are used.