- Imidazo[1,2-a]pyridine-ylmethyl-derivatives and their use as flavoring agents
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The present invention primarily relates to imidazo[1,2-a]pyridine-ylmethyl-derivatives of Formula (I) wherein R1, R2, X, W e J are as defined in the description, to mixtures thereof and to the use thereof as flavoring agents. The compounds in accordance with the present invention are suitable for producing, imparting, or intensifying an umami flavor. The invention further relates to flavoring mixtures, compositions for oral consumption as well as ready-to-eat, ready-to-use and semifinished products, comprising an effective amount of the compound of Formula (I) and to specific methods for producing, imparting, modifying and/or intensifying specific flavor impressions.
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- METHOD FOR THE PRODUCTION OF NON-AROMATIC HYDROCARBONS
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The invention relates to a method for the production of long-chain, branched-chain and/or cyclic hydrocarbons. A low molecular weight alkyl halide and a fused salt are firstly prepared. The fused salt contains an electrophilic compound and a reducing agent and is free from oxygen and oxygen compounds. The alkyl halide is then brought into contact with the fused salt such that long-chain, branched-chain and/or cyclic hydrocarbons are formed in the fused salt. The hydrocarbons formed in the fused salt are drawn off and can subsequently be separated from unreacted starting materials. By means of the above method, hydrogen can be produced during the reaction of the low molecular weight alkyl halide. The risk of oxidation of the alkane produced to give carbon monoxide or carbon dioxide is avoided by means of the reducing conditions in the fused salt. The product distribution can be controlled by means of suitable selection of the composition of the fused salt. Highly-branched hydrocarbons are produced with the preferred application of a sodium chloroaluminate fused salt.
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- Reduction of organic halides with lanthanum metal: A novel generation method of alkyl radicals
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Results of the reaction of alkyl halides with lanthanum metal have been shown. The reduction of alkyl iodide with 1/3 equiv of lanthanum metal efficiently proceeded to give the corresponding reductive dimerized products along with the formation of reduction and dehydroiodination products. In the case of alkyl bromides and chlorides, the reaction did not proceed under the same reaction conditions as that of alkyl iodides; however, the reaction was dramatically promoted by the addition of a catalytic amount of iodine. A reaction pathway including alkyl radicals was suggested.
- Nishino, Toshiki,Watanabe, Toshihisa,Okada, Mitsuo,Nishiyama, Yutaka,Sonoda, Noboru
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p. 966 - 969
(2007/10/03)
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- Selective catalytic hydrogenation of organic compounds in supercritical fluids as a continuous process
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We report a new method for continuous hydrogenation in supercritical fluids (CO2 or propane) using heterogeneous noble metal catalysts on Deloxan aminopolysiloxane supports. The method has considerable promise both for laboratory-scale hydrogenation and for the industrial production of fine chemicals. It can be applied to a wide range of organic compounds including alkenes, alkynes, aliphatic and aromatic ketones and aldehydes, epoxides, phenols, oximes, nitrobenzenes, Schiff bases, and nitriles. Conversion of starting materials, product selectivity, and space-time yields of the catalyst are all high, and the reactors themselves are very small (5- and 10-mL volume). Supercritical hydrogenation enables the reaction parameters to be controlled very precisely. Results are presented for a series of different reactions showing product distributions, which are dependent on temperature, pressure, H2 concentration, and the loading and nature of the catalyst. The hydrogenation of cyclohexene has been studied in some detail, and our results are related to the phase diagrams of the ternary system cyclohexane + CO2 + H2, which we present in a novel way, more suited to continuous reactors. Finally, we report that the supercritical hydrogenation of isophorone has advantages over conventional methods.
- Hitzler, Martin G.
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p. 137 - 146
(2013/09/08)
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- The oxidation of alkanes with dimethyldioxirane; a new mechanistic insight
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Primary kinetic isotope effects were measured for the oxidation of cyclohexane and methylcyclohexane with DMDO in solution and in the gas phase. These experiments suggest an electrophilic oxygen insertion mechanism for the oxidation of alkanes by DMDO.
- Asensio, Gregorio,Mello, Rossella,Gonzalez-Nunez, M. Elena,Boix, Carmen,Royo, Jorge
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p. 2373 - 2376
(2007/10/03)
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- Activity of copper- and iron-containing catalysts in the reaction of isophorone with ammonia and hydrogen
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An investigation has been made of the vapour-phase reaction of isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) with ammonia and hydrogen at a temperature of 160-230°C on an oxide copper-zinc-aluminium catalyst SNM-1 and a reduced, promoted, sintered iron catalyst. The composition of the main reaction products has been established, and schemes of their formation are proposed.
- Shuikin,Glebov,Marchevskaya,Kliger,Zaikin
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p. 174 - 179
(2007/10/03)
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- Direct Studies of 1,1-Diazenes. Syntheses, Infrared and Electronic Spectra, and Kinetics of the Thermal Decomposition of N-(2,2,6,6-Tetramethylpiperidyl)nitrene and N-(2,2,5,5-Tetramethylpyrrolidyl)nitrene
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The syntheses, direct spectroscopic observation, and kinetics of thermal decomposition of the persistent 1,1-diazenes, N-(2,2,6,6-tetramethylpiperidyl)nitrene (4) and N-(2,2,5,5-tetramethylpyrrolidyl)nitrene (5) are reported.The electronic absorption spectrum of 4 at -78 deg C reveals a structured absorption for the n,?* transition: λmax = 543 nm, λ0,0 = 620 nm, and εmax = 18 +/- 3 in Et2O; λmax = 541 nm and λ0,0 = 610 in CH2Cl2; λmax = 526 nm and λ0,0 = 592 nm in i-PrOH.The electronic absorption spectrum of 1,1-diazene 5 at -78 deg C reveals a structured absorption band for the n,?* transition: λmax = 497 nm and λ0,0 = 572 nm and εmax = 20 +/- 3 in CH2Cl2; λmax = 487 nm and λ0,0 = 552 nm in i-PrOH.The infrared spectrum of 4 shows a strong absorption at 1595 cm-1 (R214N=14N stretch) and provides evidence that 1,1-diazene 4 has considerable N=N double-bond character in the ground state.The infrared spectrum of 5 shows a strong absorption at 1638 cm-1 (R214N=14N stretch).The unimolecular rate of thermal decomposition of 4 is sensitive to solvent, the rate increasing with decreasing solvent polarity (krel = 1.0, 1.7, 4.8 in THF, Et2O, and hexane, respectively).The activation parameters for the unimolecular fragmentation of 1,1-diazene 4 are as follows: log A = 11.6 +/- 0.5 and Ea = 16.9 +/- 0.7 kcal mol-1 in hexane; log A = 13.7 +/- 0.3 and Ea = 20.0 +/- 0.4 kcal mol-1 in Et2O; log A = 13.6 +/- 0.3 and Ea = 20.1 +/- 0.4 kcal mol-1 in THF.The activation parameters for the bimolecular dimerization of 4 are log A = 3.8 +/- 0.7 and Ea = 6.4 +/- 0.9 kcal mol-1 in CDCl3.The unimolecular rate of thermal decomposition of 5 is sensitive to solvent, the rate increasing with decreasing solvent polarity, krel = 1.0, 2.4, and 5.1 for THF, Et2O, and hexane, respectively.The activation parameters for the unimolecular fragmentation of 1,1-diazene 5 are as follows: log A = 10.9 +/- 0.3 and Ea = 16.8 +/- 0.5 kcal mol -1 in hexane; log A = 12.4 +/- 0.4 and Ea = 19.0 +/- 0.6 kcal mol-1 in Et2O; log A = 12.1 +/- 0.3 and Ea = 19.1 +/- 0.4 kcal mol-1 in THF.At -41.1 deg C the bimolecular rate constant for the dimerization of 5 is 8.5 * 10-5 L/(mol s), 90 times slower than that found for 4.The change from a six-membered to five-membered ring 1,1-diazene causes a shift to higher energy for the n,?* transition and a shift to increased wavenumber (cm-1) for the N=N stretching frequency, not unlike that of the isoelectronic ketones, tetramethylcyclohexanone and tetramethylcyclopentanone.Similar Ea values for the unimolecular thermal fragmentation of 4 and 5 may indicate the strain energy difference between 4 and 5 is also small.An approximate value of 30.5 kcal mol-1 for the heat of formation of the 1,1-diazene 5 is estimated, indicating the 1,1-diazene 5 has a higher heat of formation than...
- Hinsberg, William D.,Schultz, Peter G.,Dervan, Peter B.
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p. 766 - 773
(2007/10/02)
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- Photochemistry of 1,1-Diazenes. Direct and Sensitized Photolyses of N-(2,2,5,5-Tetramethylpyrrolidyl)nitrene, dl-N-(2,5-Diethyl-2,5-dimethylpyrrolidyl)nitrene, and N-(2,2,6,6-Tetramethylpiperidyl)nitrene
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The photochemistry of the 1,1-diazenes N-(2,2,5,5-tetramethylpyrrolidyl)nitrene (1), dl-N-(2,5-diethyl-2,5-dimethylpyrrolidyl)nitrene (2), and N-(2,2,6,6-tetramethylpiperidyl)nitrene (3) is reported.The fluorescence spectrum of 1,1-diazene 1 has a O-O band at 607 nm, which is the maximum.The spacing between the peaks at 607 and 672 nm corresponds to the N=N stretch of S0 consistent with the 1638 cm-1 stretch obtained from the infrared spectrum of 1.The fluorescence quantum yields are ΦF = 2 x 10-3 (MTHF, -78 deg C), 7 x 10-3 (MTHF, -196 deg C), and 1 x 10-3 (EPA, -196 deg C).The fluorescence lifetime of 1 is τF = 2.3 x 10-8 s (CFCl3, -196 deg C).Direct irradiation of 1 (466-610 nm, -78 deg C) affords four hydrocarbon products, 54percent 4, 44percent 5, 2percent 6 + 7 and tetrazene 8.Triplet-sensitized photodecomposition afforded 74percent 4, 24percent 5, 2percent 6 + 7 and tetrazene 8.An approximate quantum yield for decomposition on direct irradiation is ΦD = 1.1 x 10-2.From S1, kN2 is > 3.4 x 105 s-1, and reaction of S0 with S1, kDIM, is > 4.2 x 107 L mol-1 s-1 (at -78 deg C).The spectrum of 1,1-diazene 2 reveals a structured absorption with λmax 507 nm and a O-O band at 568 nm ( ε = 20).The vibrational spacing is 1270 cm-1.The fluorescence spectrum of 1,1-diazene 2 has a O-O band at 620 nm, which is the maximum.The spacing between the maxima at 620 and 690 nm corresponds to the N=N stretch of S0 consistent with the 1630 cm-1 stretch obtained for the infrared spectrum of 2.The fluorescence quantum yield ΦF = 9 x 10-3 (MTHF, -196 deg C).The direct and sensitized irradiation of 2 in the visible affords hydrocarbon products 14-19 and tetrazene 20 in different ratios.The retention of stereochemistry in the cyclobutane products in the direct and sensitized photodecomposition was 98 and 68percent, respectively, similar to the spin correlation effect seen in corresponding 1,2-diazene isomer.This indicates that for 2 (and by extension 1) kisc N2, consistent with a large S1-T1 gap in 1,1-diazenes.For 1,1-diazene 3 the fluorescence spectrum has a single maximum at 684 nm.The fluorescence quantum yield ΦF = 4 x 10-4 (MTHF, -196 deg C).The estimated fluorescence lifetime is τ = 4 x 10-9 s.Direct irradiation of 3 in the visible at -78 deg C afforded three hydrocarbon products, 29percent 21, 68percent 23 and tetrazene 25.
- Schultz, Peter G.,Dervan, Peter B.
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p. 6660 - 6668
(2007/10/02)
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- Carbon-13 magnetic resonance: hydrogen involvement in γ-anti substituent effects
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Chemical shifts have been determined for the carbons in a series of 3,3-dimethylcyclohexyl derivatives, (substituent = H, CH3, NH2, OH, Cl, Br, I).Comparison of the γ-anti substituent effects at carbons 3 and 5 indicates that presence of axial protons on these carbons causes increased shielding by all of the above substituents.The shielding by γ-anti substituents is decreased by the replacement of either the α or γ protons by methyl groups; the extent of the decrease is dependent upon the substituent and upon the position of the hydrogen which is replaced.
- Forrest, T. P.,Thiel, J.
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p. 2870 - 2875
(2007/10/02)
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