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In depth headspace analysis of the slow degradation of β-alkylthioalkanones in ambient air led to the discovery of a novel δ-cleavage pathway, by which β-mercaptoketones are released. Since β-mercaptoketones are potent natural aroma compounds occurring in many fruits, herbs and flowers, the discovery of an enzyme-independent molecular precursor for this class of high-impact molecules is of practical importance. Moreover, the formation of β-diketones and aldehydes by concomitant oxidation at the α-sulfur-position enhances the versatility of this class of aroma precursors. A mechanistic model is proposed which suggests that the oxidative degradation occurs through a novel Pummerer-type rearrangement of initially formed persulfoxides.

Temperature-induced change in reactivity of the frequently used ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([C4C1im]BF4) is presented as a prerequisite for the rational screening of reaction courses in material synthesis. [C4C1im]BF4 becomes active with oxidic precursor compounds in reduction reaction at ?≥200 °C, even without the addition of an external reducing agent. The reaction mechanism of forming red amorphous selenium from SeO2 is investigated as a model system and can be described similarly to the Riley oxidation. The reactive species but-1-ene, which is formed during the decomposition of [C4C1im]BF4, reacts with SeO2 and form but-3-en-2-one, water, and selenium. Elucidation of the mechanism was achieved by thermoanalytical investigations. The monotropic phase transition of selenium was analyzed by the differential scanning calorimetry. Beyond, the suitability of the single source oxide precursor Bi2Se3O9 for the synthesis of Bi2Se3 particles was confirmed. Identification, characterization of formed solids succeeded by using light microscopy, XRD, SEM, and EDX.

Described herein are two different methods for the synthesis of vinyl halides by a shuttle catalysis based iridium-catalyzed transfer hydrohalogenation of unactivated alkynes. The use of 4-chlorobutan-2-one or tert-butyl halide as donors of hydrogen halides allows this transformation in the absence of corrosive reagents, such as hydrogen halides or acid chlorides, thus largely improving the functional-group tolerance and safety profile of these reactions compared to the state-of-the-art. This method has granted access to alkenyl halide compounds containing acid-sensitive groups, such as tertiary alcohols, silyl ethers, and acetals. The synthetic value of those methodologies has been demonstrated by gram-scale synthesis where low catalyst loading was achieved.

Graphene–metal nanocomposites have been found to remarkably enhance the catalytic performance of metal nanoparticle-based catalysts. In continuation of our previous report, in which highly reduced graphene oxide (HRG)-based nanocomposites were synthesized and evaluated, we present nanocomposites of graphene oxide (GRO) and ZnO nanoparticle-doped MnCO3 ([ZnO–MnCO3/(1%)GRO]) synthesized via a facile, straightforward co-precipitation technique. Interestingly, it was noticed that the incorporation of GRO in the catalytic system could noticeably improve the catalytic efficiency compared to a catalyst (ZnO–MnCO3) without GRO, for aerial oxidation of benzyl alcohol (BzOH) employing O2 as a nature-friendly oxidant under base-free conditions. The impacts of various reaction factors were thoroughly explored to optimize reaction conditions using oxidation of BzOH to benzaldehyde (BzH) as a model substrate. The catalysts were characterized using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, Energy dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET), and Raman spectroscopy. The (1%)ZnO–MnCO3/(1%)GRO exhibited significant specific activity (67 mmol.g?1.hr?1) with full convversion of BzOH and >99% BzH selectivity within just 6 min. The catalytic efficiency of the (1%)ZnO–MnCO3/(1%)GRO nanocomposite was significantly better than the (1%)ZnO–MnCO3/(1%)HRG and (1%)ZnO–MnCO3 catalysts, presumably due to the existence of oxygen-possessing groups on the GRO surface and as well as a very high surface area that could have been instrumental in uniformly dispersing the active sites of the catalyst, i.e., ZnO–MnCO3. Under optimum circumstances, various kinds of alcohols were selectively transformed to respective carbonyls with full convertibility over the (1%)ZnO–MnCO3/(1%)GRO catalyst. Furthermore, the highly effective (1%)ZnO–MnCO3/(1%)GRO catalyst could be successfully reused and recycled over five consecutive runs with a marginal reduction in its performance and selectivity.

Until now, the substitution of alcohols by N-nucleophiles via TBN-catalyzed dehydrogenation was not known. Herein, we reported a TBN catalyzed dehydrative N-alkylation of anilines with 4-hydroxybutan-2-one in the presence of TEMPO, which was different from the TEMPO/TBN catalyzed oxidation reactions. A range of anilines reacted successfully with 4-hydroxybutan-2-one to generate the N-monoalkylation products in good yields. Mechanistic studies revealed that this reaction most possibly proceeded through aza-Michael addition. Water was the only by-product, making it more environmentally friendly. The gram-scale reactions verified the synthetic practicality of this protocol.

Vapor-phase catalytic dehydration of butanediols (BDOs) such as 1,3-, 1,4-, and 2,3-butanediol was investigated over yttria-stabilized tetragonal zirconia (YSZ) catalysts as well as monoclinic zirconia (MZ). BDOs were converted to unsaturated alcohols with some by-products over YSZ and MZ. YSZ is superior to MZ for these reactions in a view point of selective formation of unsaturated alcohols. Calcination temperature of YSZ significantly affected the products selectivity as well as the conversion of BDOs: high selectivity to unsaturated alcohols was obtained over the YSZ calcined at high temperatures over 800 °C. In the conversion of 1,4-butanediol at 325 °C, the highest 3-buten-1-ol selectivity of 75.3% was obtained over the YSZ calcined at 1050 °C, whereas 2,3-butanediol was less reactive than the other BDOs. In the dehydration of 1,3-butanediol at 325 °C, in particular, it was found that a YSZ catalyst with a Y2O3 content of 3.2 wt.% exhibited an excellent stable catalytic activity: the highest selectivity to unsaturated alcohols such as 2-buten-1-ol and 3-buten-2-ol over 98% was obtained at a conversion of 66%. Structures of active sites for the dehydration of 1,3-butanediol were discussed using a crystal model of tetragonal ZrO2 and a probable model structure of active site was proposed. The well-crystalized YSZ inevitably has oxygen defect sites on the most stable surface of tetragonal ZrO2 (101). The defect site, which exposes three cations such as Zr4+ and Y3+, is surrounded by six O2? anions. The selective dehydration of 1,3-butanediol to produce 3-buten-2-ol over the YSZ could be explained by tridentate interactions followed by sequential dehydration: the position-2 hydrogen is firstly abstracted by a basic O2? anion and then the position-1 hydroxyl group is subsequently or simultaneously abstracted by an acidic Y3+ cation. Another OH group at position 3 plays an important role of anchoring 1,3-butanediol to the catalyst surface. Thus, the selective dehydration of 1,3-butanediol could proceed via the speculative base-acid-concerted mechanism.

Pyrolysis of Au(OAc)3 in the presence of 1,10-phenanthroline over TiO2 furnishes a highly active and selective Au nanoparticle (NP) catalyst embedded in a nitrogen-doped carbon support, Au@N-doped carbon/TiO2 catalyst. Parameters such as pyrolysis temperature, type of support, and nitrogen ligands as well as Au/ligand molar ratios were systematically investigated. Highly selective hydrogenation of numerous structurally diverse alkynes proceeded in moderate to excellent yield under mild conditions. The high selectivity toward the industrially important alkene substrates, functional group tolerance, and the high recyclability makes the catalytic system unique. Both high activity and selectivity are correlated with a frustrated Lewis pairs interface formed by the combination of gold and nitrogen atoms of N-doped carbon that, according to density functional theory calculations, can serve as a basic site to promote the heterolytic activation of H2 under very mild conditions. This "fully heterogeneous" and recyclable gold catalyst makes the selective hydrogenation process environmentally and economically attractive.

Zinc oxide nanoparticles doped manganese carbonate catalysts [X% ZnOx-MnCO3] (where X = 0-7) were prepared via a facile and straightforward coprecipitation procedure, which upon different calcination treatments yields different manganese oxides, that is, [X% ZnOx-MnO2] and [X% ZnOx-Mn2O3]. A comparative catalytic study was conducted to evaluate the catalytic efficiency between carbonates and oxides for the selective oxidation of secondary alcohols to corresponding ketones using molecular oxygen as a green oxidizing agent without using any additives or bases. The prepared catalysts were characterized by different techniques such as SEM, EDX, XRD, TEM, TGA, BET, and FTIR spectroscopy. The 1% ZnOx-MnCO3 calcined at 300°C exhibited the best catalytic performance and possessed highest surface area, suggesting that the calcination temperature and surface area play a significant role in the alcohol oxidation. The 1% ZnOx-MnCO3 catalyst exhibited superior catalytic performance and selectivity in the aerial oxidation of 1-phenylethanol, where 100% alcohol conversion and more than 99% product selectivity were obtained in only 5 min with superior specific activity (48 mmol·g-1·h-1) and 390.6 turnover frequency (TOF). The specific activity obtained is the highest so far (to the best of our knowledge) compared to the catalysts already reported in the literatures used for the oxidation of 1-phenylethanol. It was found that ZnOx nanoparticles play an essential role in enhancing the catalytic efficiency for the selective oxidation of alcohols. The scope of the oxidation process is extended to different types of alcohols. A variety of primary, benzylic, aliphatic, allylic, and heteroaromatic alcohols were selectively oxidized into their corresponding carbonyls with 100% convertibility without overoxidation to the carboxylic acids under base-free conditions.

The gas phase hydrogenation of 3-butyne-2-one, an alkynic ketone, over two alumina-supported palladium catalysts is investigated using infrared spectroscopy in a batch reactor at 373?K. The mean particle size of the palladium crystallites of the two catalysts are comparable (2.4?±?0.1?nm). One catalyst (Pd(NO3)2/Al2O3) is prepared from a palladium(II) nitrate precursor, whereas the other catalyst (PdCl2/Al2O3) is prepared using palladium(II) chloride as the Pd precursor compound. A three-stage sequential process is observed with the Pd(NO3)2/Al2O3catalyst facilitating complete reduction all the way through to 2-butanol. However, hydrogenation stops at 2-butanone with the PdCl2/Al2O3catalyst. The inability of the PdCl2/Al2O3catalyst to reduce 2-butanone is attributed to the inaccessibility of edge sites on this catalyst, which are blocked by chlorine retention originating from the catalyst's preparative process. The reaction profiles observed for the hydrogenation of this alkynic ketone are consistent with the site-selective chemistry recently reported for the hydrogenation of crotonaldehyde, an alkenic aldehyde, over the same two catalysts. Thus, it is suggested that a previously postulated structure/activity relationship may be generic for the hydrogenation of α,β-unsaturated carbonyl compounds over supported Pd catalysts.

The heterogeneous interaction of isoprene with TiO2 surfaces was studied under dark and UV light irradiation conditions. The experiments were conducted at room temperature, using zero air as bath gas, in a flow reactor coupled with a SIFT-MS (selected-ion flow-tube mass spectrometer) and a FTIR spectrometer for the gas-phase monitoring of reactants and products. The steady-state uptake coefficient and the yields of the products formed were measured as a function of TiO2 mass (9–120 mg), light intensity (37–112 W m?2), isoprene concentration (36–12000 ppb), and relative humidity (0.01–90% of RH). Under dark and dry conditions, isoprene was efficiently and reversibly adsorbed on TiO2. In contrast, under humid conditions, isoprene uptake was diminished, pointing to competitive adsorption with water molecules. In the presence of UV light irradiation, isoprene reacted on the surface of TiO2. The reactive steady-state uptake coefficient, γss, was independent of RH under most ambient relative humidity conditions (>50%). However, γss was strongly dependent on isoprene initial concentration according to the empirical expression: γss = (2.0 × 10?4) × [isoprene]0?n with n = 0.35 and 0.28 for 37 and 112 W m?2 irradiation conditions, respectively. In addition to the kinetics, a detailed product study was performed. The gas-phase oxidation products were mostly CO2 (ca. 90% of the carbon mass balance) and a large variety of carbonyl compounds (methyl vinyl ketone, acetone, methacrolein, formaldehyde, acetaldehyde, propanal, traces of butanal, and pentanal), the distribution of which was investigated as a function of mineral oxide mass, isoprene concentration, and RH. Furthermore, the surface-adsorbed products were determined employing off-line HPLC chromatography; their concentrations were inversely dependent on RH and decreased to background levels at RH greater than 30%. Finally, the reaction mechanism and possible implications of isoprene reaction on TiO2 are briefly discussed.

An acid-base bifunctional catalyst was synthesized by treating a natural mixed-metal oxide, serpentine, with sulfuric acid. Catalyst characterization revealed that the number of acidic and basic sites increased after the acid treatment largely due to an increase in surface area. However, stronger acid sites were also introduced by the formation of bridged hydroxyl groups between a Si atom and a heteroatom, as inferred by H NMR and NH3-TPD analysis. Results from SEM-EDS and 1H NMR suggested that the acid and base sites were in close proximity. Catalytic conversions of carbohydrate-derived bio-oil model compounds were performed over different acid/base catalysts. Eight single bio-oil model compounds and two binary mixtures were used. The reactivity of the model compounds was found to be strongly correlated to the number of oxygen-containing functional groups in the reactant. The results from the binary mixtures showed that the acid-base bifunctional catalyst had the highest activity in aldol condensation reactions. The best deoxygenation performance was also observed with the bifunctional catalyst for the model compounds. Reaction pathways were proposed on the basis of an isotope labeling study. Deoxygenation reactions were found to be promoted by the cooperative catalysis between closely located acid and base sites.

We report the catalytic chromium-mediated oxidation of secondary allylic alcohols to give α,β-unsaturated aldehydes with exclusive (E)-stereoselectivity. This facile procedure employs catalytic PCC (5?mol?%) and periodic acid (H5IO6) as a co-oxidant. This transformation occurs specifically with aromatic substituted allyl alcohols containing both electron withdrawing and electron donating substituents as well as a range of functional groups.

Allylic alcohols were exploited as synthetic precursors of γ-keto sulfones. The reaction involved the one-pot generation of α,β-enones in situ from the allylic alcohols by using a PdII–dioxygen catalytic system and subsequent sulfa-Michael addition in the presence of water. Importantly, water was identified as a sustainable substitute for a toxic copper salt to promote organosulfonyl addition. Diverse examples of aromatic and aliphatic γ-keto sulfones were prepared. Specially, Ar–X (X = Br, Cl) bonds were tolerated, which indicated a chemoselective catalytic system for the preparation of halogen-bearing γ-keto sulfones. This one-pot method does not require an acid, a base, or isolation of any intermediate. Control experiments indicated that the active catalyst of the first step also promoted the subsequent C–S bond-formation reaction. Water was found to accelerate the reaction rate and to be involved in the protonolysis of the σ-alkylpalladium complex, as corroborated by deuterium incorporation.

A commercial Pd catalyst based on Sibunit carbon support was treated with H6TeO6 in a reducing media to obtain a Te coating on the surface of Pd particles. The PdTe/C catalyst prepared in this way showed the ability to control the radical chain oxidation of 1,3-butadiene by promoting the selective formation of 2-butene-1,4-diol, 4-hydroxybut-2-enal and furan in DMA (total selectivity of 61% and yield of 7%). At the same time, the catalyst induced oxidation of 1,3-butadiene by a non-radical heterolytic mechanism involving the formation of two groups of primary products: (1) crotonaldehyde and methyl vinyl ketone and (2) the products of oxygenation at the 1,4-positions. The compounds of the second group including 1,4-dimethoxy-2-butene and maleic acid dimethyl ester were formed on PdTe centers in MeOH. Increasing the Te concentration in the PdTe/C catalyst forced the conversion of 1,3-butadiene toward 1,4-oxygenation and simultaneously decreased the intensity of secondary oxidation, resulting in the selective formation of derivatives of the 1,4-oxygenation - 1,4-dimethoxy-2-butene and allenic alcohol methyl ether (total selectivity of 84% and yield of 48%).

Designed catalyst poisons can be deliberately added in various reactions for tuning chemoselectivity. In general, the poisons are "transient" selectivity modifiers that are readily leached out during reactions and thus should be continuously fed to maintain the selectivity. In this work, we supported Pd catalysts on a thermochemically stable cross-linked polymer containing diphenyl sulfide linkages, which can simultaneously act as a catalyst support and a "permanent" selectivity modifier. The entire surfaces of the Pd clusters were ligated (or poisoned) by sulfide groups of the polymer support. The sulfide groups capping the Pd surface behaved like a "molecular gate" that enabled exceptionally discriminative adsorption of alkynes over alkenes. H2/D2 isotope exchange revealed that the capped Pd surface alone is inactive for H2 (or D2) dissociation, but in the presence of coflowing acetylene (alkyne), it becomes active for H2 dissociation as well as acetylene hydrogenation. The results indicated that acetylene adsorbs on the Pd surface and enables cooperative adsorption of H2. In contrast, ethylene (alkene) did not facilitate H2-D2 exchange, and hydrogenation of ethylene was not observed. The results indicated that alkynes can induce decapping of the sulfide groups from the Pd surface, while alkenes with weaker adsorption strength cannot. The discriminative adsorption of alkynes over alkenes led to highly chemoselective hydrogenation of various alkynes to alkenes with minimal overhydrogenation and the conversion of side functional groups. The catalytic functions can be retained over a long reaction period due to the high thermochemical stability of the polymer.

The invention relates to a process comprising reacting mevalonic acid, or a solution comprising mevalonic acid, to yield a first product or first product mixture, optionally in the presence of a solid catalyst and/or at elevated temperature and/or pressure. The invention further relates to a process comprising: (a) providing a microbial organism that expresses a biosynthetic mevalonic acid pathway; (b) growing the microbial organism in fermentation medium comprising suitable carbon substrates, whereby biobased mevalonic acid is produced; and (c) reacting said biobased mevalonic acid to yield a first product or first product mixture.

Dihydroisoquinoline reacts with Danishefsky's diene under Lewis acidic conditions or neat, to give low to moderate yields of the formal aza-Diels-Alder, [4+2]-cycloadduct. However, using methoxyvinyl methylketone with Lewis acid catalysis does not give the aza-Diels-Alder adduct, rather a formal [2+2+2]-cycloaddition occurs to provide access to a diacetyl dihydropyridine. Increased Lewis acid loading results in reduced dihydropyridine formation, and instead, a trimerisation reaction of the methoxyvinyl methyl ketone occurs, to give 1,3,5-triacetylbenzene from a different formal [2+2+2]-cycloaddition. The formal [4+2]-cycloaddition reaction of methoxyvinyl methylketone requires a cyclic imine in order to form the dihydropyridine because the reaction with acyclic imines produced a dihydropyridine from a formal [1+2+1+2]-cycloaddition. Evidence resulting from the isolation of reaction intermediates and in situ spectroscopic studies, shows that the reaction between 3,4-dihydroisoquinoline and methyl vinyl ketone, catalysed by oxy-philic Lewis acids, proceeds via a Mannich-Michael pathway and an imminium ion species. All reactions occur by one-pot cascade routes.

Disclosed is a method for preparing aqueous nanoparticle suspensions of derivatives of 4,9-dihydroxy-naphtho[2,3-b]furan aliphatic acid esters. The compositions and the uses of the aqueous nanoparticle suspensions prepared according to the method as described herein are also disclosed.

The oxidative and reductive electrochemical conversion of levulinic acid to its primary products valeric acid, γ-valerolactone, 2,7-octanedione, 4-hydroxy-2-butanone and 3-buten-2-one is studied in detail. The reactions were performed in aqueous solutions and at ambient temperature, following the principles of green chemistry. The obtained primary reaction products were studied with respect to the oxidative and reductive electrochemical formation of secondary products, such as n-octane, 1-butanol and 1,3-butanediol. It is shown that the choice of electrolyte composition, educt concentration and the nature of the electrode material has a strong influence on the selectivity of product formation. For instance it is demonstrated that in alkaline solutions γ-valerolactone can be gained from levulinic acid at iron electrodes with similar Coulombic efficiency (～20%) but higher selectivity (S = 70%) than on lead (S = 50%). Furthermore, for the first time the electrochemical two-step reaction of levulinic acid to 1-butanol via 4-hydroxy-2-butanone is reported. For some of the reaction pathways the main product is water insoluble, which allows a direct separation of the product and the potential electrolyte reuse in a semi-continuous process. Especially the use of the electrocatalytic hydrogenation may provide a path for the storage of electricity into liquid organic fuels as shown by a basic energetic assessment of all electrochemical conversions.

Focusing on the marine-derived alkaloid ageladine A ([4-(4,5-dibromo-1H-pyrrol-2-yl)]-1H-imidazo[4,5-c]pyridin-2-amine trifluoroacetate), we combined and modified published strategies to develop a synthesis method with easily managed reaction steps that allows gram-scale batch synthesis. On exploration additional features of the fluorescent properties of the compound were revealed. In tissues and cells of a marine flatworm, the emission profile shifted to longer wavelengths than in water. The fluorescence emission maximum shifted around 30-450 nm and the profile showed sufficient intensity at approximately 550 nm and above.

The reaction of N-(2-pyridylmethyl)iminodiethanol (H2pmide) and Fe(NO3)3·9H2O in MeOH led to the formation of a dimeric iron(iii) complex, [(Hpmide)Fe(NO3)] 2(NO3)2·2CH3OH (1). Its anion-exchanged form, [(pmide)Fe(N3)]2 (2), was prepared by the reaction of 1 and NaN3 in MeOH, during which the Hpmide ligand of 1 was also deprotonated. These compounds were investigated by single crystal X-ray diffraction and magnetochemistry. In complex 1, one iron(iii) ion was bonded with a mono-deprotonated Hpmide ligand and a nitrate ion. The two iron(iii) ions within the dinuclear unit were connected by two ethoxy groups with an inversion center. In 2, one iron(iii) ion was coordinated with a deprotonated pmide ligand and an azide ion. The Fe(pmide)(N3) unit was related by symmetry through an inversion center. Both 1 and 2 efficiently catalyzed the oxidation of a variety of alcohols under mild conditions. The oxidation mechanism was proposed to involve an FeIVO intermediate as the major reactive species and an FeVO intermediate as a minor oxidant. Evidence for this proposal was derived from reactivity and Hammett studies, KIE (kH/kD) values, and the use of MPPH (2-methyl-1-phenylprop-2-yl hydroperoxide) as a mechanistic probe. Both compounds had significant antiferromagnetic interactions between the iron(iii) ions via the oxygen atoms. 1 showed a strong antiferromagnetic interaction within the Fe(iii) dimer, while 2 had a weak antiferromagnetic coupling within the Fe(iii) dimer.

Highly ordered mesoporous alumina was prepared via evaporation induced self assembly and was impregnated to afford a family of Pd/meso-Al2O 3 catalysts for the aerobic selective oxidation (selox) of allylic alcohols under mild reaction conditions. CO chemisorption and XPS identify the presence of highly dispersed (0.9-2 nm) nanoparticles comprising heavily oxidised PdO surfaces, evidencing a strong palladium-alumina interaction. Surface PdO is confirmed as the catalytically active phase responsible for allylic alcohol selox, with initial rates for Pd/meso-Al2O 3 far exceeding those achievable for palladium over either amorphous alumina or mesoporous silica supports. Pd/meso-Al2O3 is exceptionally active for the atom efficient selox of diverse allylic alcohols, with activity inversely proportional to alcohol mass.

Chemoselective oxidation of allylic alcohols to α,β-unsaturated carbonyl compounds proceeded efficiently using hydrogen peroxide with iron-picolinate catalysts. The in situ generated [Fe(Me-Pic)3] (Me-Pic = 6-methylpicolinate) catalyzed oxidation of the alcohol moiety of primary allylic alcohols while the [Fe(Pic)3] (Pic = picolinate) and [Fe(Me-Pic)2(Pic)] did not show sufficient catalytic activity. the Partner Organisations 2014.

A highly enantioselective intramolecular 6-exo-trig aza-Michael addition was developed to afford chiral 3-substituted 1,2-oxazinanes in high yields (up to 99% yield) and good enantioselectivities (up to 98/2 er). These reactions were enabled by a quinine-derived primary-tertiary diamine as a catalyst and pentafluoropropionic acid (PFP) as a co-catalyst.

Chemoselective oxidation of allylic alcohols to α,β-unsaturated carbonyl compounds proceeded efficiently using hydrogen peroxide with iron-picolinate catalysts. The in situ generated [Fe(Me-Pic)3] (Me-Pic = 6-methylpicolinate) catalyzed oxidation of the alcohol moiety of primary allylic alcohols while the [Fe(Pic)3] (Pic = picolinate) and [Fe(Me-Pic)2(Pic)] did not show sufficient catalytic activity. This journal is

Thiazolium carbene-catalyzed reaction of aromatic 1,2-diketones with enones in aprotic solvents gave double acylation products in good yields, whereas hydroacylation products formed by Stetter reaction were not detected at all. These results suggested the generation of aroyloxyenamine species from the 1,2-diketones instead of hydroxyenamines (Breslow intermediates). This journal is

Using oxygen as the sole oxidant for two steps, we developed a new method to synthesize β-aryl α,β-enones by fine-tuning the Pd(ii)-catalyzed oxidation of allyl alcohol to subsequent arylation with arylboronic acids, arylboronic ester and aryltrifluoroborate salt. This one-pot green method does not require copper salt, base, and intermediate isolation. Halogen-bearing chalcones, dibenzylideneacetones and arylalkyl enones were synthesized in good yields. This journal is

Treatment of N,N-dimethyl-N′-(2-pyridyl)formamidine with methyl vinyl ketone under microwave irradiation yields N-formyl-N-(3-oxobutyl)-2- pyridylamine without decomposition or polymerization of methyl vinyl ketone. The result is an alternative non-oxidat

Site modification and isolation through selective poisoning comprise an effective strategy to enhance the selectivity of palladium catalysts in the partial hydrogenation of triple bonds in acetylenic compounds. The recent emergence of supported hybrid materials matching the stereo- and chemoselectivity of the classical Lindlar catalyst holds promise to revolutionize palladium-catalyzed hydrogenations, and will benefit from an in-depth understanding of these new materials. In this work, we compare the performance of bare, lead-poisoned, and ligand-modified palladium catalysts in the hydrogenation of diverse alkynes. Catalytic tests, conducted in a continuous-flow three-phase reactor, coupled with theoretical calculations and characterization methods, enable elucidation of the structural origins of the observed selectivity patterns. Distinctions in the catalytic performance are correlated with the relative accessibility of the active site to the organic substrate, and with the adsorption configuration and strength, depending on the ensemble size and surface potentials. This explains the role of the ligand in the colloidally prepared catalysts in promoting superior performance in the hydrogenation of terminal and internal alkynes, and short-chain alkynols. In contrast, the greater accessibility of the active surface of the Pd-Pb alloy and the absence of polar groups are shown to be favorable in the conversion of alkynes containing long aliphatic chains and/or ketone groups. These findings provide detailed insights for the advanced design of supported nanostructured catalysts. Hybrid nanocatalysts: The classical Lindlar and the newly developed NanoSelectTM catalysts are confronted in the semi-hydrogenation of alkynes (see figure). Systematic testing under continuous-flow three-phase conditions, coupled with detailed characterization analyses and molecular simulations, enable the understanding of the structure of the catalysts and the associated activity and selectivity patterns for a wide range of acetylenic compounds.

Biomass-derived short-chain polyols can be transformed into valuable oxygenates used as building blocks. The gas phase conversion of a model molecule of 1,3-diols (1,3-butanediol), was studied on bifunctional Cu-Mg, Cu-Al and Cu-Mg-Al mixed oxide catalysts that exhibit surface Cu0 particles and acid-base properties. A series of ZCuMgAl catalysts (Z = 0.3-61.2 wt.% Cu, Mg/Al = 1.5 molar ratio) was prepared by coprecipitation and thoroughly characterized by several techniques such as BET surface area, TPR-N2O chemisorption, XRD and TPD of CO2. The ZCuMgAl catalysts promote the upgrading of diols by a series of dehydrogenation and/or dehydration reactions proceeding at reaction rates that depend on the copper content (Z). The overall activity increases linearly with the amount of surface Cu0 species thereby confirming the participation of metallic sites in the rate-limiting steps. Besides, surface Cu0 sites favor the reaction pathway toward 1,3-butanediol dehydrogenation. Thus, the dehydrogenation/dehydration selectivity ratio increases with Z as a result of the enhanced amount of exposed Cu0 particles. ZCuMgAl catalysts with Z 4 ketones and break the intermediates forming C1-C 3 oxygenates; catalysts with Z > 8 wt.% have higher activity and yield valuable multifunctional C4 oxygenates such as hydroxyketones and, to a lesser extent, unsaturated alcohols and ketones. A strongly basic Cu-Mg catalyst promotes the C-C bond cleavage reaction giving short carbon chain oxygenates at low rates; an acidic Cu-Al catalyst converts the diol into C 4 saturated ketones and olefins. the Partner Organisations 2014.

The low-temperature oxidation of the five hexane isomers (n-hexane, 2-methyl-pentane, 3-methyl-pentane, 2,2-dimethylbutane, and 2,3-dimethylbutane) was studied in a jet-stirred reactor (JSR) at atmospheric pressure under stoichiometric conditions between 550 and 1000 K. The evolution of reactant and product mole fraction profiles were recorded as a function of the temperature using two analytical methods: gas chromatography and synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS). Experimental data obtained with both methods were in good agreement for the five fuels. These data were used to compare the reactivity and the nature of the reaction products and their distribution. At low temperature (below 800 K), n-hexane was the most reactive isomer. The two methyl-pentane isomers have about the same reactivity, which was lower than that of n-hexane. 2,2-Dimethylbutane was less reactive than the two methyl-pentane isomers, and 2,3-dimethylbutane was the least reactive isomer. These observations are in good agreement with research octane numbers given in the literature. Cyclic ethers with rings including 3, 4, 5, and 6 atoms have been identified and quantified for the five fuels. While the cyclic ether distribution was notably more detailed than in other literature of JSR studies of branched alkane oxidation, some oxiranes were missing among the cyclic ethers expected from methyl-pentanes. Using SVUV-PIMS, the formation of C 2-C3 monocarboxylic acids, ketohydroperoxides, and species with two carbonyl groups have also been observed, supporting their possible formation from branched reactants. This is in line with what was previously experimentally demonstrated from linear fuels. Possible structures and ways of decomposition of the most probable ketohydroperoxides were discussed. Above 800 K, all five isomers have about the same reactivity, with a larger formation from branched alkanes of some unsaturated species, such as allene and propyne, which are known to be soot precursors.

The development of a descriptor or descriptors that can relate the activity of catalysts to their physical properties is a major objective of catalysis research. In this study, we have found that the apparent activation energy for propene oxidation to acrolein over scheelite-structured, multicomponent, mixed metal oxides (Bi3FeMo2O12, Bi2Mo2.5W0.5O12, and Bi1-x/3V1-xMoxO4, where 0 x 1) correlates with the band gap of the catalyst measured at reaction temperature. We show through theoretical analysis of the energy components comprising the activation energy why the band-gap energy is the primary component dependent on catalyst composition and, hence, why one should expect the activation energy for propene oxidation to correlate with the band-gap energy. We also demonstrate that the change in band-gap energy with composition arises from the interplay between the sizes and energies of the V 3d, Fe 3d, Mo 4d, and W 5d orbitals, which give rise to the lowest unoccupied crystal orbitals. Both the utility of the band-gap energy as a descriptor for catalytic activity and the role of orbital overlap in determining the band gap are likely to be general features in mixed metal oxide oxidation catalysts, enabling the rational design of catalysts with greater activity for oxidation reactions.

Disclosed is a method for preparing aqueous nanoparticle suspensions of derivatives of 4,9-dihydroxy-naphtho[2,3-b]furan aliphatic acid esters. The compositions and the uses of the aqueous nanoparticle suspensions prepared according to the method as described herein are also disclosed.

The present invention discloses use of prodrug of 4,9-dihydroxy-naphtho[2,3-b]furan derivative for circumventing cancer multidrug resistance. The present invention also discloses use of prodrug of 4,9-dihydroxy-naphtho[2,3-b]furan derivative for the treatment of various types of cancers exhibiting multidrug resistance phenomenon. The present invention further discloses use of the pharmaceutically acceptable composition comprising prodrug of 4,9- dihydroxy-naphtho[2,3-b]furan derivative and method of using said composition in the treatment of various types of cancers exhibiting multidrug resistance phenomenon.

The present invention discloses esters of 4,9-dihydroxy-naphtho[2,3-b]furans and methods of making and using the same. The present invention also discloses conversion of the esters into therapeutically active 4,9-dihydroxy-naphtho[2,3-b]furans in vivo. The present invention furthermore discloses pharmaceutical compositions comprising the esters of 4,9-dihydroxy-naphtho[2,3-b]furans for the treatment of various indications including proliferative diseases.

Surfactant templating offers a simple route to synthesize high-surface area silicas with ordered, tunable mesopore architectures. The use of these materials as versatile catalyst supports for palladium nanoparticles has been explored in the aerobic selective oxidation (selox) of allylic alcohols under mild conditions. Families of Pd/mesoporous silicas, synthesized through incipient wetness impregnation of SBA-15, SBA-16, and KIT-6, have been characterized by using nitrogen porosimetry, CO chemisorption, diffuse reflection infrared Fourier transform spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and high-resolution TEM and benchmarked in liquid phase allylic alcohol selox against a Pd/amorphous SiO2 standard. The transition from amorphous to two-dimensional parallel and three-dimensional interpenetrating porous silica networks conferred significant selox rate enhancements associated with higher surface densities of active palladium oxide sites. Dissolved oxygen was essential for insitu stabilization of palladium oxide, and thus maintenance of high activity on-stream, whereas selectivity to the desired aldehyde selox product over competing hydrogenolysis pathways was directed by using palladium metal.

A novel selective two-step synthesis of β-isothiocyanato ketones from α,β-unsaturated ketones has been developed. The synthesis includes preparation of β-azido ketones followed by reaction with triphenylphosphine and carbon disulfide. Treatment of the obtained β-isothiocyanato ketones with ammonia or methylamine gives corresponding hexahydro-4-hydroxypyrimidine-2- thiones. The latter are also prepared directly from β-azido ketones without isolation of the intermediate β-isothiocyanato ketones.

A process of oxidizing primary alcohols to their corresponding aldehydes is disclosed. The process is effected in the presence of noble metal polyoxometalate complexes. A novel process for preparing noble metal polyoxometalate complexes, and novel noble metal polyoxometalate complexes are also disclosed.

The present invention discloses esters of 4,9-dihydroxy-naphtho[2,3-b]furans and methods of making and using the same. The present invention also discloses conversion of the esters into therapeutically active 4,9-dihydroxy-naphtho[2,3-b]furans in vivo. The present invention furthermore discloses pharmaceutical compositions comprising the esters of 4,9- dihydroxy-naphtho[2,3-b]furans for the treatment of various indications including proliferative diseases.

Phosphanylferrocenecarboxamide Ph2P-fc-CONHCH2CH 2OH (1, fc = ferrocene-1,1′-diyl) and its newly synthesized congeners, Ph2P-fc-CONHCH(CH2OH)2 (2) and Ph2P-fc-CONHC(CH2OH)3 (3), were converted to a series of (η6-arene)ruthenium complexes [(η6- arene)RuCl2(L-κP)] 5-7, where arene is benzene, p-cymene, and hexamethylbenzene and L = 1-3. All compounds were characterized by multinuclear NMR and IR spectroscopy, by mass spectrometry, and by elemental analysis. The molecular structures of 2, 3, 3O (a phosphane oxide resulting from the oxidation of 3), 5c·CH2Cl2, and 6c·Et2O were determined by single-crystal X-ray diffraction analysis. The ruthenium complexes were further evaluated as catalysts in the redox isomerization of allyl alcohols to carbonyl compounds. Complex [(η6-p-cymene) RuCl2(1-κP)] (5b) proved to be a particularly attractive catalyst, being both readily available and catalytically active. Substrates with unsubstituted double bonds were cleanly isomerized with this catalyst in 1,2-dichloroethane (0.5 mol-% Ru, 80 °C), whereas for those bearing substituents at the double bond (particularly in the position closer to the OH group) lower conversions and selectivities were achieved. A similar trend was noted when pure water was used as the solvent, except that the best results (complete conversion with 2 mol-% Ru) were seen for 1,3-diphenylallyl alcohol, the most hydrophobic substrate.

New air-stable, water-soluble Ru(II)-phosphane complexes were synthesized in high purity by the reaction of cis-[RuCl2(dmso)4] with 2 equivalents of 1,3,5-triaza-7-phosphaadamantane (pta) and its N-methyl and N-benzyl derivatives (pta-Me and pta-Bn, respectively). All new complexes were characterized by elementary analysis and spectroscopic methods (NMR, ESI-MS) and the molecular structures of cis-cis-trans-[RuCl2(dmso) 2(pta)2], cis-cis-trans-[RuCl2(dmso) 2(pta-H)2]Cl2 (obtained in acidic solutions) and that of cis-cis-trans-[RuCl2(dmso)2(pta-Me) 2](CF3SO3)2 were determined by single crystal X-ray diffraction. Under mild conditions, cis-[RuCl 2(dmso)4] actively catalyzed the transformation of allylic alcohols into the corresponding ketones with 100% selectivity while in the same reaction the new Ru(II)-pta complexes showed moderate activity and selectivity.

Reactions of alkenols with H2O2 - LiBr - Ce(NO 3)3·6H2O or H2O2 - LiBr - Ce(NH4)2(NO3)6 system led to bromination of the double bond to yield vicinal dibromoalkanols. The reaction proceeded highly selectively, no oxidation of the hydroxyl group virtually occurred.

A catalyst, its method of preparation and its use for producing aliphatic ketones by subjecting alkanes C3 to C9 to a gas phase catalytic oxidation in the presence of air or oxygen, and, optionally, steam and / or one or more diluting gases. The catalyst comprises a catalytically active mixed metal oxide phase and a suitable support material onto and / or into which the active catalytic phase is dispersed.

Second-order rate constants were determined for the oxidation of 27 alcohols (R1R2CHOH) by a carbocationic oxidizing agent, 9-phenylxanthylium ion, in acetontrile at 60°C. Alcohols include open-chain alkyl, cycloalkyl, and unsaturated alcohols. Kinetic isotope effects for the reaction of 1-phenylethanol were determined at three H/D positions of the alcohol (KIEα-D=3.9, KIEβ-D3=1.03, KIE OD=1.10). These KIE results are consistent with those we previously reported for the 2-propanol reaction, suggesting that these reactions follow a hydride-proton sequential transfer mechanism that involves a rate-limiting formation of the α-hydroxy carbocation intermediate. Structure-reactivity relationship for alcohol oxidations was deeply discussed on the basis of the observed structural effects on the formation of the carbocationic transition state (Cδ+-OH). Efficiencies of alcohol oxidations are largely dependent upon the alcohol structures. Steric hindrance effect and ring strain relief effect win over the electronic effect in determining the rates of the oxidations of open-chain alkyl and cycloalkyl alcohols. Unhindered secondary alkyl alcohols would be selectively oxidized in the presence of primary and hindered secondary alkyl alcohols. Strained C7-C11 cycloalkyl alcohols react faster than cyclohexyl alcohol, whereas the strained C5 and C12 alcohols react slower. Aromatic alcohols would be efficiently and selectively oxidized in the presence of aliphatic alcohols of comparable steric requirements. This structure-reactivity relationship for alcohol oxidations via hydride-transfer mechanism is hoped to provide a useful guidance for the selective oxidation of certain alcohol functional groups in organic synthesis. Copyright

Synchronous, time-resolved DRIFTS/MS/XAS cycling studies of the vapor-phase selective aerobic oxidation of crotyl alcohol over nanoparticulate Pd have revealed surface oxide as the desired catalytically active phase, with dynamic, reaction-induced Pd redox processes controlling selective versus combustion pathways.

Chemical equations presented. The hydride affinities of 21 typical aldehydes and ketones in acetonitrile were determined by using an experimental method, which is valuable for chemists choosing suitable reducing agents to reduce them. The focus of this paper is to introduce a very facile experimental method, which can be used to determine the hydride affinities of various carbonyl compounds in solution.

The oxidative decarboxylation of levulinic acid (LA) by silver(I)/persulfate [Ag(I)/S2O82-] has been investigated in this paper. The effects of buffer solution, initial pH value, time and temperature and dosages of Ag(I)/S2O8 2- on the decarboxylation of LA were examined in batch experiments and a reaction scheme was proposed on basis of the reaction process. The experimental results showed that a solution of NaOH-KH2PO4 was comparatively suitable for the LA decarboxylation reaction by silver(I)/persulfate. Under optimum conditions (temperature 160 °C, pH 5.0, and time 0.5 h), the rate of LA conversion in NaOH-KH2PO4 solutions with an initial concentration of 0.01 mol LA reached 70.2%, 2-butanone (methyl ethyl ketone) was the single product in the gas phase and the resulted molar yield reached 44.2%.

A method for converting levulinic acid to methyl vinyl ketone is described. The method includes the steps of reacting an aqueous solution of levulinic acid, over an acid catalyst, at a temperature of from room temperature to about 1100 K. Methyl vinyl ketone is thereby formed.

Cyclopropylhydroxycarbene was generated by high-vacuum flash pyrolysis of cyclopropylglyoxylic acid at 960 °C. The pyrolysis products were matrix-isolated in solid Ar at 11 K and characterized by means of IR spectroscopy. Upon photolysis, the carbene undergoes ring expansion, thereby paralleling the reactivity of other known cyclopropylcarbenes. The ring expansion product, cyclobut-1-en-1-ol, was characterized for the first time. Matrix-isolated cyclopropylhydroxycarbene undergoes [1,2]H-tunneling through a barrier of approximately 30 kcal·mol-1, yielding cyclopropylcarboxaldehyde. The cyclopropyl moiety acts as a π-donor and increases the half-life by almost a factor of 10 compared to parent hydroxymethylene, resulting in a temperature-independent half-life of τ = 17.8 h at both 11 and 20 K. Hence, cyclopropylhydroxycarbene is the first hydroxycarbene that differs from other members of its family by a significantly prolonged half-life. As expected, the O-deuterated analogue does not show tunneling. Our findings are rationalized by accurate CCSD(T)/cc-pVnZ (n = D, T)//M06-2X/6-311++G(d,p) computations. The half-life of cyclopropylhydroxycarbene was verified by tunneling computations employing the Wentzel-Kramers-Brillouin formalism. By comparison with other experimentally known hydroxycarbenes, we determine the electronic donor capabilities of the carbenes' substituents to be a dominant factor governing their half-lives.

A hexadecyltrimethylammonium salt of a "sandwich" type polyoxometalate has been used as a ligand to attach a palladium(II) center. This Pd-POM compound was an active catalyst for the fast aerobic oxidation of alcohols. The unique property of this catalyst is its significant preference for the oxidation of primary versus secondary aliphatic alcohols. Since no kinetic isotope effect was observed for the dehydrogenation step, this may be the result of the intrinsically higher probability for oxidation of primary alcohols attenuated by steric factors as borne out by the higher reactivity of 1-octanol versus 2-ethyl-1-hexanol. The reaction is highly selective to aldehyde with little formation of carboxylic acid; autooxidation is inhibited. No base is required to activate the alcohol. The fast reactions appear to be related to the electron-acceptor nature of the polyoxometalate ligand that may also facilitate alcohol dehydrogenation in the absence of base.