Ketone Carbonyl Group Research Articles

Poly(4-ketovalerolactone) from Levulinic acid: Synthesis and Hydrolytic Degradation.

We report here the synthesis of poly(4-ketovalerolactone) (PKVL) via ring-opening transesterification polymerization (ROTEP) of the monomer 4-ketovalerolactone (KVL, two steps from levulinic acid). The polymerization of KVL proceeds to high equilibrium monomer conversion (up to 96% in the melt) to give the semicrystalline polyketoester PKVL with low dispersity. PKVL displays glass transition temperatures of 7 °C and two melting temperatures at 132 and 148 °C. This polyester can be chemically recycled through hydrolytic degradation. Under aqueous neutral or acidic conditions, the dominating pathway for polyester hydrolysis is through backbiting from the chain end. Under basic conditions, mid-chain cleavage, accelerated by the ketone carbonyl group in the backbone, promotes the hydrolysis of nearby backbone ester bonds. The final hydrolysis product is 5-hydroxylevulinic acid, the ring opened hydrolysis product of KVL. PKVL was also observed to degrade under the action of a Brønsted acid to a bis-spirocyclic dilactone natural product altaicadispirolactone, which is a dimer of KVL. This constitutes a rare example of a one-step synthesis of a secondary metabolite of non-trivial structure in which a polymer was the starting material and the sole source of matter. Analogous ROTEP of the isomeric 4-membered lactone 4-acetyl-β-propiolactone (APL) was also explored, although this chemistry was not as well-behaved as the KVL to PKVL polymerization.

Synthesis, Characterization and Microbicides Activities of N-(hydroxy-4-((4-nitrophenyl)diazenyl)benzylidene)-2-(phenylamino)acetohydrazide metal complexes

VO(II), Cu(II), Ni(II), Co(II), Mn(II), Fe(III), Ru(III) , Zn(II) and UO2(II) complexes of hydra-zone ligand containing azo group as side chain were prepared from condensation of 2-hydroxy-4-((4-nitrophenyl)diazenyl) benzylidene)benzaldehyde with 2-(phenyl amino)acetohydrazide. The ligand and its complexes were isolated in solid state and characterized by analytical techniques such as elemental analyses, molar conductance, magnetic susceptibility measurements and Electronic spin resonance (ESR) as well as spectroscopic techniques such as UV-Visible, IR, 1H-NMR and 13C- NMR. The spectral data indicated that the ligand acted as neutral bidentate or monobasic tridentate ligand bonded to the metal ions through an oxygen atom of ketonic or enolic carbonyl group, an azomethine nitrogen atom and deprotonated phenolic oxygen atom forming either tetragonally distorted octahedral or square planer geometry. ESR spectra of the solid metal complexes (2-6) and (8) were studied. Antimicrobial activities of the ligand and its complexes were evaluated against E. coli, Bacillus subtilis and Aspergillus Niger by well diffusion method. Results showed that the complex (10) exhibited higher antifungal activity, complex (7) exhibited higher antibacterial than the other complexes against E. coli, while complex (10) exhibited higher antibacterial against B.subtilis than the other complexes.

Synthesis of 13,14-Dehydro-15-deoxy-16-hydroxy-16-methyl-17-phenoxyprostaglandin B1 Ethyl Ester

A new synthetic route has been developed for the construction of the main skeleton of ω-aryloxyprostaglandin (PG) via 1,2-addition of lithiated 3-methyl-3-(trimethylsilyloxy)pent-1-yne to the ketone carbonyl group of ethyl 7-(5-oxocyclopent-1-en-1-yl)heptanoate. The addition reaction was accompanied by the formation of cyclopentenone dimer as minor product. The 1,2-adduct containing a tertiary hydroxy group was oxidized with pyridinium chlorochromate to 13-dehydro-PGB1 ethyl ester.

Binding of N8-Acetylspermidine Analogues to Histone Deacetylase 10 Reveals Molecular Strategies for Blocking Polyamine Deacetylation.

Eukaryotic histone deacetylase 10 (HDAC10) is a Zn2+-dependent hydrolase that exhibits catalytic specificity for the hydrolysis of the polyamine N8-acetylspermidine. The recently determined crystal structure of HDAC10 from Danio rerio (zebrafish) reveals a narrow active site cleft and a negatively charged "gatekeeper" (E274) that favors the binding of the slender cationic substrate. Because HDAC10 expression is upregulated in advanced-stage neuroblastoma and induces autophagy, the selective inhibition of HDAC10 suppresses the autophagic response and renders cancer cells more susceptible to cytotoxic chemotherapeutic drugs. Here, we describe X-ray crystal structures of zebrafish HDAC10 complexed with eight different analogues of N8-acetylspermidine. These analogues contain different Zn2+-binding groups, such as hydroxamate, thiolate, and the tetrahedral gem-diolate resulting from the addition of a Zn2+-bound water molecule to a ketone carbonyl group. Notably, the chemistry that accompanies the binding of ketonic substrate analogues is identical to the chemistry involved in the first step of catalysis, i.e., nucleophilic attack of a Zn2+-bound water molecule at the scissile carbonyl group of N8-acetylspermidine. The most potent inhibitor studied contains a thiolate Zn2+-binding group. These structures reveal interesting geometric changes in the metal coordination polyhedron that accommodate inhibitor binding. Additional interactions in the active site highlight features contributing to substrate specificity. These interactions are likely to contribute to inhibitor binding selectivity and will inform the future design of compounds selective for HDAC10 inhibition.

Renewable sources: applications in personal care formulations.

A global tendency for products considered environmentally sustainable, and ecologically obtained led the industry related to personal care formulations to fund the research and the development of personal care/cosmetics containing ingredients from natural resources. Furthermore, consumers are aware of environmental and sustainability issueans, thus not harming the environment represents a key consideration when developing a new cosmetic ingredient. In this study we review some examples of active ingredients or raw materials used in cosmetics/personal care/biomedical products that are coming from either through biotechnological systems, or as byproducts of several industries. A skin formulation containing biosynthetic actives, prepared by us and the study regarding its dermocosmetic properties are also described. The need for the standardization processes, the safety assessment tools, the improvement of the exploitation methods of these renewable sources in order the production to be ecologically and economically better are also discussed.

Synthesis, Characterization and biological Study of some new derivatives from Pregnenolone via McMurry reaction

A series of some new Pregnenolone derivatives have been synthesized by McMurry reaction which include using of (Low-Valent) titanium from (TiCl4) with (Zn-dust) as catalyst and (THF) as a solvent to convert the (ketonic carbonyl group) of Pregnenolone with a new aldehyde or ketone compound to a new aliphatic double bond connected each other. All the new synthesized derivatives were monitored by (TLC) and assigned by elemental analysis, melting points, FT-IR and (1H NMR, 13C NMR and 2D-NMR) spectroscopy. The anti-bacterial and anti-fungi activity of these derivatives were also determined.

A Ba/Pd Catalytic System Enables Dehydrative Cross-Coupling and Excellent E-Selective Wittig Reactions.

A Ba/Pd cooperative catalysis system was developed to enable the dehydrative cross-coupling of allylic alcohols with P-ylides to occur directly and promote a subsequent Wittig reaction in one pot. A variety of multisubstituted 1,4-dienes were isolated in good to excellent yields with broad P-ylides (stabilized by both ester and ketone carbonyl groups) and aldehyde (aliphatic and aromatic) substrates with excellent E selectivity.

Construction of pyridinium/N-chloramine polysiloxane on cellulose for synergistic biocidal application

Cotton cellulose was modified with polysiloxane with dual antimicrobial groups of pyridinium and N-chloramine (N-Cl) to endorse enhanced synergistic biocidal ability. A new compound, 4-oxo-N-(pyridin-4-yl)pentanamide (OPPA), that contains precursors of both pyridinium and N-chloramine was synthesized via amidation of 4-oxopentanoic acid and 4-aminopyridine. The molecules of OPPA were connected to cotton cellulose using poly(methylhydrosiloxane) (PMHS) as linker through hydrosilylation reaction between some Si–H groups of PMHS and hydroxyl groups of cellulose and some other Si–H groups and ketone carbonyl groups of OPPA. The OPPA on cellulose was transformed into its biocidal counterpart after quaternization of the pyridine to pyridinium and chlorination of the amide N–H to N-chloramine. The synthetic procedures and modification results were characterized with Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy. The pyridinium/N-chloramine polysiloxane layer on cellulose was estimated to be 77 nm by weight and provided powerful and synergistic antibacterial capacities against model species of Escherichia coli and Staphylococcus aureus. The stability of the polysiloxane modifier layer and the rechargeability of lost chlorine were promising under repeated washing, long-term storage, and UV irradiation. The presented pyridinium/N-chloramine polysiloxane layer showed advantages over many of the current systems containing either cationic salt or N-chloramine due to the synergism.

Defect-Enriched N,O-Codoped Nanodiamond/Carbon Nanotube Catalysts for Styrene Production via Dehydrogenation of Ethylbenzene

Owing to the unique structure and enriched surface ketonic carbonyl group, nanodiamond (ND) shows excellent catalytic performance for dehydrogenation reaction. However, the agglomeration of predisp...

Connecting a carbonyl and a π-conjugated group through a p-phenylene linker by (5+1) benzene ring formation.

A benzene ring was formed to connect a carbonyl group of various methyl ketones with a π-conjugated group through a p-phenylene linker. Methyl ketones and streptocyanines were used as the C1 and C5 sources, respectively, in the (5+1) annulation, which could form donor-π-acceptor molecules.

Nanodiamond@carbon nitride hybrid with loose porous carbon nitride layers as an efficient metal-free catalyst for direct dehydrogenation of ethylbenzene

This work presents a facile and low-cost approach to prepare nanodiamond@carbon nitride hybrid with loose porous carbon nitride layers close wrapped on well dispersed NDs (ND-CN) through the thermal polymerization of the mixture composed of hexamethylenetetramine (HTM) and ammonium chloride adsorbed on dispersed nanodiamonds (ND), in which hexamethylenetetramine serves as both carbon nitride precursor and dispersing agent and the ammonium chloride acts as gas template. ND-CN shows 1.9 and 1.2 times much higher styrene rate for oxygen and steam-free direct dehydrogenation of ethylbenzene than the pristine ND and the previously reported carbon nitride layers encapsulated ND (H-ND) formed by the thermal polymerization of mixture composed of HTM and ND, respectively, ascribed the more exposed active sites containing structural defects and ketonic carbonyl groups and the not weakened synergistic effect of carbon nitride with ND that originating from the enlarging surface area and pore volume owing to the characteristic concerning loose porous structure of carbon nitride layers.

Regioselective and Stereoselective Reductive Aziridinium Ring Cleavage Leading to Azabicyclodecane Architecture: Enantioselective Synthesis of (+)-Subincanadine F.

Enantioselective synthesis of cytotoxic indole alkaloid (+)-subincanadine F was accomplished starting from the corresponding ( S)-acetoxysuccinimide via aziridinium ring formation and its reductive ring expansion route. Regioselective and stereoselective reductive aziridinium carbon-nitrogen bond cleavage comprising ring expansions was a key step. The ( S)-OMOM protection of the hydroxyl moiety adjacent to a benzylic carbon of an in situ formed aziridinium system was necessary for lithium borohydride-induced reductive ring expansions, and it also served as a latent source of an essential ketone carbonyl group for the generation of an α,β-conjugated system.

Oxidative dehydrogenation of ethyl lactate over nanocarbon catalysts: Effect of oxygen functionalities and defects

Pyruvic acid and pyruvate derivatives are important chemical intermediates which are normally produced using metal-based catalytic materials that could cause serious environmental problems. In the present work, renewable nanocarbon catalysts are applied in this system, and a solvent free and highly selective oxidative dehydrogenation of ethyl lactate (EL) process is achieved to produce ethyl pyruvate (EP) under mild reaction conditions. Chemical titration results provide direct evidence that ketonic carbonyl groups on nanocarbon are active sites for this reaction. Raman, XPS and model catalyst experimental results have shown that there is a dynamic transformation between defects and oxygen functionalities during the catalytic reactions. The reaction pathway is revealed via kinetic analysis, which may shed light on the rational design of carbon catalysts and their potential catalytic applications in the field of fine chemical productions.

Dynamic Kinetic Resolution of Heterobiaryl Ketones by Zinc-Catalyzed Asymmetric Hydrosilylation.

A diastereo- and highly enantioselective dynamic kinetic resolution (DKR) of configurationally labile heterobiaryl ketones is described. The DKR proceeds by zinc-catalyzed hydrosilylation of the carbonyl group, thus leading to secondary alcohols bearing axial and central chirality. The strategy relies on the labilization of the stereogenic axis that takes place thanks to a Lewis acid-base interaction between a nitrogen atom in the heterocycle and the ketone carbonyl group. The synthetic utility of the methodology is demonstrated through stereospecific transformations into either N,N-ligands or appealing axially chiral, bifunctional thiourea organocatalysts.

Dynamic Kinetic Resolution of Heterobiaryl Ketones by Zinc‐Catalyzed Asymmetric Hydrosilylation

AbstractA diastereo‐ and highly enantioselective dynamic kinetic resolution (DKR) of configurationally labile heterobiaryl ketones is described. The DKR proceeds by zinc‐catalyzed hydrosilylation of the carbonyl group, thus leading to secondary alcohols bearing axial and central chirality. The strategy relies on the labilization of the stereogenic axis that takes place thanks to a Lewis acid–base interaction between a nitrogen atom in the heterocycle and the ketone carbonyl group. The synthetic utility of the methodology is demonstrated through stereospecific transformations into either N,N‐ligands or appealing axially chiral, bifunctional thiourea organocatalysts.

Identification and Regulation of Active Sites on Nanodiamonds: Establishing a Highly Efficient Catalytic System for Oxidation of Organic Contaminants

AbstractNanodiamonds exhibit great potential as green catalysts for remediation of organic contaminants. However, the specific active site and corresponding oxidative mechanism are unclear, which retard further developments of high‐performance catalysts. Here, an annealing strategy is developed to accurately regulate the content of ketonic carbonyl groups on nanodiamonds; meanwhile other structural characteristics of nanodiamonds remain almost unchanged. The well‐defined nanodiamonds with well‐controlled ketonic carbonyl groups exhibit excellent catalytic activity in activation of peroxymonosulfate for oxidation of organic pollutants. Based on the semi‐quantitative and quantitative correlations of ketonic carbonyl groups and the reaction rate constants, it is conclusively determined that ketonic carbonyl groups are the catalytically active sites. Different from conventional oxidative systems, reactive oxygen species in nanodiamonds@peroxymonosulfate system are revealed to be singlet oxygen with high selectivity, which can effectively oxidize and mineralize the target contaminants. Impressively, the singlet‐oxygen‐mediated oxidation system significantly outperforms the classical radicals‐based oxidation system in remediation of actual wastewater. This work not only provides a valuable insight for the design of new nanocarbon catalysts with abundant active sites but also establishes a very promising catalytic oxidation system for the green remediation of actual contaminated water.

An Efficient Metal-Free Catalyst for Oxidative Dehydrogenation Reaction: Activated Carbon Decorated with Few-Layer Graphene.

Activated carbon (AC) has been widely used in the catalysis field because of its low cost, scalable production, high specific surface area, and abundant exposed edge. Because of the amorphous structure, traditional AC is unstable in presence of O2 at high temperature, which hinders the application of AC catalysts in oxidative dehydrogenation (ODH) of alkanes. Here, partially graphitic AC decorated with few-layer graphene is facilely fabricated by simple high-temperature calcination. The graphitic transformation significantly enhances the antioxidation property, long-term stability of AC during the ODH reaction, and especially dramatically increases the graphitic edge areas in which the active ketonic carbonyl groups are selectively formed in ODH reactions. A high reactivity with 41.5 % selectivity and 13.2 % yield to C4 alkenes were obtained at 450 °C over the optimized catalyst, which is superior to all the previously reported carbon catalysts and shows a great potential for industrial application.

Boron-doped graphene as a metal-free catalyst for gas-phase oxidation of benzyl alcohol to benzaldehyde.

Boron-doped graphene samples (BGs) with tunable boron content of 0–2.90 at% were synthesized and directly used in the gas-phase oxidation of benzyl alcohol to benzaldehyde, and showed excellent performance. XPS results indicated that the graphitic sp2 B species (BC3) is the mainly boron dopant species incorporated in the graphene lattice, which could significantly improve the content of ketone carbonyl groups (C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> O) on the graphene. For instance, the contents of CO jumped from 1.93 to 4.19 at% while BC3 doped into the graphene lattice was only 0.35 at%. The CO is the active site of catalytic reaction, so BG has significantly improved catalytic activity. Compared to the un-doped graphene (G), the conversion of benzyl alcohol over BGs increased 2.35 times and the selectivity of benzaldehyde increased from 77.3% to 99.2%. Aerobic–anaerobic exchange experiments revealed that the superior catalytic performance of BG was achieved only under aerobic conditions. The study of the boron-doped carbocatalyst may also provide guidance for the design of surface modified carbon-based catalysts for the selective oxidation dehydrogenation of alcohols by regulating doping elements and their types.

Modification of polycarbonate surface in oxidizing plasma

The properties of the surface of the film polycarbonate Lexan 8010 were experimentally studied after treatment in a DC discharge plasma in oxygen and air at pressures of 50-300 Pa and a discharge current of 80 mA. The contact angles of wetting and surface energies are measured. The topography of the surface was investigated by atomic force microscopy. The chemical composition of the surface was determined from the FT-IR spectroscopy data in the variant of total internal reflection, as well as X-ray photoelectron spectroscopy. Treatment in the oxidizing plasma leads to a change in morphology (average roughness increases), an increase in the surface energy, and the concentration of oxygen-containing groups (hydroxyl groups, carbonyl groups in ketones or aldehydes and in oxyketones) on the surface of the polymer. Possible reasons for the difference in surface properties of polymer under the action of oxygen and air plasma on it are discussed.

The role of pyruvic acid as starting material in some organic reactions in the presence of SBA-Pr-SO3H nanocatalyst

Pyruvic acid contains three different reactive positions: –COOH, ketone carbonyl and methyl groups. Correspondingly, pyruvic acid was applied as starting material in the modified Niementowski reaction and Aldol condensation using SBA-Pr-SO3H as an efficient nanocatalyst. Aldol condensation of pyruvic acid and oxindole provided a new oxindol-based carboxylic acid which was subsequently used in the Ugi four-component reaction. Moreover, through the modified Niementowski reaction of pyruvic acid, new derivatives of quiazoline were produced in the presence of SBA-Pr-SO3H. The obtained products are important due to their potentially biological active skeletons.