Series Of Ketones Research Articles

Relationship between proton affinities and structures of proton-bound dimers

This work presents a structural approach for determination of proton affinities of molecules. In proton-bound dimer [X…H…M]+, M and X compete with each other to capture the proton. The correlation between proton affinities of a series of molecules, M, and X…H bond length was studied while X was a common molecule in the all proton-bound dimers. Linear relationships were observed between proton affinities of a series of alcohols, ethers, aldehydes, ketones and amines and X…H bond length, where H2O and HF were used as X. The method was employed for the measurement of proton affinities of (HF)1-10 clusters using NH3 and H2O as common molecules, [NH3…H…(HF)n]+ and [H2O…H…(HF)n]+. A linear correlation was observed for the PAs of (HF)n clusters versus N…H bond length.

Practical Access to Difluoromethyl Ketones via Straightforward Decarboxylative Difluorination of β‐Ketoacids

AbstractA facile synthetic approach to a series of difluoromethyl ketones from β‐ketoacids has been described. This transformation is achieved through the straightforward decarboxylative difluorination of β‐ketoacids in the absence of any catalyst. Furthermore, the resulted difluoromethyl ketones can be easily converted into corresponding difluoromethylated building blocks for pharmaceuticals and materials.magnified image

An efficient FeCl3-mediated approach for reduction of ketones through N-heterocyclic carbene boranes

An efficient FeCl3-mediated approach for reduction of ketones by NHC-BH3 has been developed. A series of ketones were smoothly converted to the corresponding alcohols in good to excellent yields through NHC-BH3 reductive process.

Performance and selectivity of cationic nanoparticle pseudo‐stationary phases in electrokinetic chromatography

Electrokinetic chromatography (EKC) is a powerful analytical technique that uses an ionic pseudo-stationary phase (PSP) to separate neutral compounds. Although anionic surfactants are the most common choice for PSP, cationic latex nanoparticles are an attractive alternative. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize several types of diblock copolymers that self-assemble into latex nanoparticles, which were characterized by a variety of techniques including diffusion NMR. The performance of each nanoparticle as a PSP was studied by using a homologous series of ketones and linear solvation energy relationships (LSER) analysis. A cationic homopolymer coating was found to be necessary to prevent band broadening caused by analyte interactions with nanoparticles adsorbed to the capillary surface. No significant difference in methylene selectivity or LSER parameters was observed between nanoparticles with different cationic shells, but differences were observed between nanoparticles with different hydrophobic cores. Cationic latex nanoparticles behaved more like anionic latex nanoparticles than like cationic surfactants, suggesting that selectivity is primarily driven by the hydrophobic portion of a PSP. Cationic latex nanoparticles in combination with a homopolymer cationic capillary coating are an excellent choice for EKC analyses where an anodic electroosmotic flow is required.

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.

Stereoselective Access to 1-[2-Bromo(het)aryloxy]propan-2-amines Using Transaminases and Lipases; Development of a Chemoenzymatic Strategy Toward a Levofloxacin Precursor.

Two independent enzymatic strategies have been developed toward the synthesis of enantioenriched 1-[2-bromo(het)aryloxy]propan-2-amines. With that purpose a series of racemic amines and prochiral ketones have been synthesized from commercially available 2-bromophenols or brominated pyridine derivatives bearing different pattern substitutions in the aromatic ring. Biotransamination experiments have been studied using ketones as starting materials, yielding both the (R)- and (S)-amine enantiomers with high selectivity (91-99% ee) depending on the transaminase source. In a complementary approach, the classical kinetic resolutions of the racemic amines have been investigated using Candida antarctica lipase type B as biocatalyst. Ethyl methoxyacetate was found as a suitable acyl donor leading to the corresponding (S)-amines (90-99% ee) and (R)-amides (88-99% ee) with high selectivity in most of the cases. A preparative biotransamination process has been developed for the synthesis of (2S)-1-(6-bromo-2,3-difluorophenoxy)propan-2-amine in 61% isolated yield after 24 h, a valuable precursor of the antimicrobial agent Levofloxacin.

Reconstruction of the Catalytic Pocket and Enzyme–Substrate Interactions To Enhance the Catalytic Efficiency of a Short‐Chain Dehydrogenase/Reductase

AbstractTo upgrade the short‐chain dehydrogenase/reductase EbSDR8 to a powerful tool for the synthesis of antiPrelog chiral alcohols, rational design was performed by reconstructing the catalytic pocket and enzyme–substrate interactions. The resulting variants showed significantly improved catalytic efficiency (kcat/KM; kcat=turnover rate, KM=Michaelis constant) towards a series of prochiral ketones, with kcat/KM values more than 15‐fold greater than that of wildtype EbSDR8 in some cases. More importantly, none of the mutations caused an adverse effect on the stereoselectivity. The increased steric repulsion and the C−H⋅⋅⋅π interaction involving the alkyl side chain of L153 and the phenyl ring of the substrate turned out to be crucial factors connected to the enhanced enzymatic activity. This provided new insight into the role of steric hindrance and non canonical interactions in protein engineering. Furthermore, the recombinant E. coli whole cells expressing the EbSDR8 variant G94A/S153L successfully catalyzed the reduction of a high‐concentration 2,2,2‐trifluoroacetophenone. The results demonstrated the effectiveness of rational design and the applicability of the designed variants in the efficient reduction of prochiral ketones.

Molecule structural factors influencing the loading of flavoring compounds in a natural-preformed capsule: Yeast cells

Yeast cells are efficient microcapsules for the encapsulation of flavoring compounds. However, as they are preformed capsules, they have to be loaded with the active. Encapsulation efficiency is to a certain level correlated with LogP. In this study, the effect of structural factors on the encapsulation of amphiphilic flavors was investigated. Homological series of carboxylic acids, ethyl esters, lactones, alcohols and ketones were encapsulated into the yeast Yarrowia lipolytica. Although, in a single homological series, the length of the molecule and thus the LogP were correlated with encapsulation efficiency (EY%), big differences were observable between series. For instance, carboxylic acids and lactones exhibited EY% around 45%–55%, respectively, for compounds bigger than C8 and C6, respectively, whereas ethyl esters reached only about 15–20% for C10 compounds. For a group of various C6-compounds, EY% varied from 4% for hexanal to 45% for hexanoic acid although the LogP of the two compounds was almost similar at 1.9. In total our results point out the importance of the level of polarity and localization of the polar part of the compound in addition to the global hydrophobicity of the molecule. They will be of importance to optimize the encapsulation of mixtures of compounds.

ChemInform Abstract: Broensted Acid Mediated N—O Bond Cleavage for α‐Amination of Ketones Through the Aromatic Nitroso Aldol Reaction.

AbstractA series of amino ketones is prepared by a nitroso aldol reaction of aromatic nitroso compounds with disilanyl enol esters and a subsequent N—O bond cleavage by treatment with phenylboronic acid or during the purification by silica gel column chromatography.

Mutual Cooperation in the Formal Allyl Alcohol Nucleophilic Substitution and Hydration of Alkynes for the Construction of γ-Substituted Ketones.

Mutual cooperation in the formal allyl alcohol nucleophilic substitution reaction and hydration of an alkyne has been utilized in the presence of a gold catalyst to give a series of γ-functionalized ketones with high to excellent yields. This reaction actually involved an intramolecular O-H insertion cyclization of an alkyne to form the dihydrofuran intermediate, which was followed by the nucleophilic addition ring-opening of a dihydrofuran to give the target compound.

Application of Deep Eutectic Solvents in Promiscuous Lipase‐Catalysed Aldol Reactions

AbstractThe application of deep eutectic solvents has been demonstrated for the first time in promiscuous lipase‐catalysed aldol reactions. The model reaction between 4‐nitrobenzaldehyde and acetone was examined in depth, with excellent compatibility being found between porcine pancreas lipase and choline chloride/glycerol mixtures for the formation of the aldol product in high yields. The system was compatible with a series of aromatic aldehydes and ketones including acetone, cyclopentanone and cyclohexanone. In some cases, the corresponding α,β‐unsaturated carbonyl compounds were found as minor products. Control experiments demonstrate that the enzymatic preparation was also responsible for a collateral dehydration reaction once the aldol product is formed.

ChemInform Abstract: Copper Catalyzed Oxygen Assisted C(CNOH)—C(Alkyl) Bond Cleavage: A Facile Conversion of Aryl/Aralkyl/Vinyl Ketones to Aromatic Acids.

A novel copper-catalyzed aerobic oxidative C(NOH)–C(alkyl) bond cleavage reaction of aryl/aralkyl/vinyl ketones for the synthesis of aromatic/acrylic acids is described. A series of ketones having aryl/aralkyl/vinyl at the one end and methyl to any higher alkyl at the other end can be selectively cleaved and converted into the corresponding acids via oxime intermediates.

ChemInform Abstract: Room‐Temperature Decarboxylative Couplings of α‐Oxocarboxylates with Aryl Halides by Merging Photoredox with Palladium Catalysis.

AbstractThe title reaction provides access to a series of aromatic and heteroaromatic ketones (III) and (VI) as well as amides (IX) in good yields and with high functional‐group compatibility.

Взаимосвязь энергии гельмгольца с температурой вспышки веществ в гомологических рядах н-алкилэтаноатов, н-спиртов и кетонов

The number of organic compounds exceeded 20 million and increases each year by 300 thousand. To ensure the fire safety and technological calculations of processes of production, for storage and transportation materials there are needed data rates fire and explosion hazard substances. To elucidate how the thermodynamic properties of liquid compounds are related to their molecular characteristics, it is necessary to study the properties of compounds in homologous series. The available methods for calculating the properties of multi component systems are also based on the properties of the constituent components. As objects of research there were selected substances homologous series of n-alkyletanoats, aliphatic ketones and alcohols. At various temperatures vapor pressure and density of the liquids in the homologous series were measured. Lewis-Randal calculations do not allow us to directly relate the thermodynamic function values of substances to the molecular weight (structure) of chemical substance. As a reference for calculating the contributions from intermolecular interaction, we used an ideal gas at the temperature, volume of a real liquid and obeying the same statistics. Based on experimental data and using the standard of ideal gas (taken at the temperature and volume of liquid) there are calculated the values internal energy, entropy, and Helmholtz energy. The analysis determined that values of thermodynamic functions are linearly dependent on the molecular weight of the substance in the homologous series. Analysis of published data established as a linear dependence of the flash point of substances of molecular weight substances in the homologous series. Considering the tendency of change these properties it's established that the flash point of substances linearly dependent on the values of the energy of Helmholtz of substances homologous series. The corresponding equations were obtained. The established regularities and obtained based on these equations allow us to predict the properties of homologous series of substances with the necessary accuracy for practical purposes.

Ferrocenyl-derived electrophilic phosphonium cations (EPCs) as Lewis acid catalysts.

Oxidation of diphenylphosphinoferrocene and 1,1'-bis(diphenylphosphino)ferrocene with XeF2, resulted in the formation of CpFe(η(5)-C5H4PF2Ph2) 1 and Fe(η(5)-C5H4PF2Ph2)22 respectively. Subsequent reactions with [SiEt3][B(C6F5)4] yielded [CpFe(η(5)-C5H4PFPh2)][B(C6F5)4] 3 and [Fe(η(5)-C5H4PFPh2)2] [B(C6F5)4]24. PhP(η(5)-C5H4)2Fe 5 was prepared, converted to [PhMeP(η(5)-C5H4)2Fe][O3SCF3] 6 and then to [PhMeP(η(5)-C5H4)2Fe][B(C6F5)4] 7. The ability of the salts 3, 4 and 7 to catalyze Friedel-Crafts dimerization of 1,1-diphenylethylene, dehydrocoupling of phenol and triethylsilane, deoxygenation of acetophenone and hydrodefluorination of 1-fluoropentane were probed. While compound 7 proved to be ineffective, compounds 3 and 4 were useful Lewis acid catalysts. Compounds 3 and 4 were shown to catalyze the deoxygenation of a series of ketones.

Synthesis of Ferrocenyl Thioketones and their Reactions with Diphenyldiazomethane

GRAPHICAL ABSTRACT

ChemInform Abstract: Pinacol Couplings of a Series of Aldehydes and Ketones with SmI2/Sm/Me3SiCl in DME.

AbstractFollowing the title reaction, aryl aldehydes and arylmethyl ketones are transformed to the corresponding pinacol coupling products in high yields and as mixtures of dl and meso diastereomers.

Ruthenium (II) complexes of NO ligands: Synthesis, characterization and application in transfer hydrogenation of carbonyl compounds

New Schiff base ligands including azo group such as (4-((E)-(4-ethylphenyl)diazenyl)-2-((E)-(phenylimino)methyl)phenol 2, 4-((E)-(4-ethylphenyl)diazenyl)-2-((E)-(naphthalen-1-ylimino)methyl)phenol 3, 2-((E)-(benzylimino)methyl)-4-((E)-(4-ethylphenyl)diazenyl)phenol 4 and azo group-free ligand (E)-2-((benzylimino)methyl)phenol 8 and their ruthenium complexes 5–7 and 9 with [RuCl2(p-cymene)] were synthesized and characterized by spectroscopic techniques including 1H and 13C NMR, FT-IR and UV–Vis. According to the UV–visible, IR and NMR data, the Ru (II) complexes 5–7 and 9 are formed by the coordination of N, O atoms of the ligands. Molecular structures of the complex 7 and complex 9 were determined by single crystal X-ray diffraction studies. These Ruthenium (II) complexes 5–7 and 9 were used as catalysts for the transfer hydrogenation of a series of ketones and benzaldehyde in 2-propanol. Following the comparison of complex 9 with the other three azo containing complexes 5–7, it was observed that azo group has got remarkable increasing effect on the catalytic activity. The results showed that the complex 5 is efficient than the other Ru (II) complexes.

ChemInform Abstract: Facile Protocol for Catalytic Frustrated Lewis Pair Hydrogenation and Reductive Deoxygenation of Ketones and Aldehydes.

A series of ketones and aldehydes are reduced in toluene under H2 in the presence of 5 mol % B(C6F5)3 and either cyclodextrin or molecular sieves affording a facile metal-free protocol for reduction to alcohols. Similar treatment of aryl ketones resulted in metal-free deoxygenation yielding aromatic hydrocarbons.

ChemInform Abstract: Alkyl—Aryl Ketone Synthesis via Nickel‐Catalyzed Reductive Coupling of Alkyl Halides with Aryl Acids and Anhydrides.

AbstractA series of ketones (III) and (V) is readily prepared by a Ni‐catalyzed reductive coupling of halides (I) and (IV) with aryl acids (II).