- KINETIC RESOLUTION OF 4-HYDROXY-2-CYCLOPENTENONE BY RHODIUM-CATALYZED ASYMMETRIC ISOMERIZATION
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Cationic Rh-BINAP complexes catalyze isomerization of racemic 4-hydroxy-2-cyclopentenone to 1,3-cyclopentadione with 5:1 enantiomeric discrimination.
- Kitamura, M.,Manabe, K.,Noyori, R.
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- Bio-based synthesis of cyclopentane-1,3-diamine and its application in bifunctional monomers for poly-condensation
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A novel and green route for the synthesis of cyclopentane-1,3-diamine (CPDA) from hemicellulosic feedstock is established in this work. Through many explorations and optimizations, the single successful multi-step synthesis was found to comprise: (1) the Piancatelli rearrangement of furfuryl alcohol to 4-hydroxycyclopent-2-enone (4-HCP), (2) a highly improved isomerization of4-HCPinto cyclopentane-1,3-dione (CPDO) using the Ru Shvo catalyst, (3) conversion ofCPDOinto cyclopentane-1,3-dioxime (CPDX), and (4) a mild oxime hydrogenation ofCPDXover Rh/C to afford the desiredCPDA. In addition, diastereomerically purecis- andtrans-isomers ofCPDAwere reacted with (A) bio-based lactones, and (B) 5-(hydroxymethyl)furfural (HMF) to synthesize novel bifunctional diol monomers with internal amide and imine groups, respectively. Monomer5, derived using γ-valerolactone (GVL), was successfully applied in the synthesis of polyurethanes.
- Alsters, Paul L.,De Wildeman, Stefaan M. A.,Hadavi, Darya,Han, Peiliang,Mogensen, Siri,Monsegue, Luciano G.,Noordijk, Jurrie,Quaedflieg, Peter J. L. M.,Verzijl, Gerard K. M.,van Slagmaat, Christian A. M. R.
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p. 7100 - 7114
(2021/09/28)
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- Rapid and Multigram Synthesis of Vinylogous Esters under Continuous Flow: An Access to Transetherification and Reverse Reaction of Vinylogous Esters
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An environmentally benign approach for the synthesis of vinylogous esters from 1,3-diketone and its reverse reaction under continuous-flow has been developed with alcohols in the presence of inexpensive Amberlyst-15 as a catalyst. This methodology is highly selective and general for a range of cyclic 1,3-dicarbonyl compounds which gives a library of linear alkylated and arylated vinylogous esters in good to excellent yield under solvent and metal free condition. Furthermore, the long-time experiment in a continuous-flow up to 40 h afforded 8.0 g of the vinylogous ester with turnover number (TON) = 28.6 and turnover frequency (TOF) = 0.715 h-1 using Amberlyst-15 as a catalyst. Furthermore, a continuous-flow sequential transetherification of vinylogous esters with various alcohols has been achieved in high yield. Reversibly, this vinylogous ester was deprotected or hydrolyzed into ketone using environmentally benign water as a solvent and Amberlyst-15 as a catalyst under continuous-flow process.
- Mohanta, Nirmala,Chaudhari, Moreshwar B.,Digrawal, Naveen Kumar,Gnanaprakasam, Boopathy
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p. 1034 - 1045
(2019/05/24)
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- Direct amination of bio-alcohols using ammonia
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A slightly adapted catalyst system has been successfully applied in the direct amination of primary and secondary alcohols. Moreover, the applicability to diols has been shown, giving high selectivity towards the primary diamines. It was found that the Ru/P ratio as well as the amount of ammonia used are highly important in this system, especially for higher substrate loadings. The catalyst was employed on a larger batch scale for the conversion of isomannide to the corresponding diamine. Additionally, it was shown that the catalyst is stable for at least six consecutive runs. No significant loss of activity and selectivity was observed.
- Pingen, Dennis,Diebolt, Olivier,Vogt, Dieter
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p. 2905 - 2912
(2013/10/21)
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- PROCESS FOR PRODUCTION OF SUBSTITUTED CYCLOPENTANONE
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A substituted cyclopentanone represented by the formula (2) can be produced by hydrogenating the double bond in a compound represented by the formula (1) in the presence of a transition metal catalyst by using a carboxylic acid or a specific concentration of a carboxylic acid ester as a solvent. This process can produce a substituted cyclopentanone which is useful as an jasmine-flavored fragrance, an intermediate in the production of the fragrance or the like, in a simple and inexpensive manner at a high cis-form ratio; (1) wherein R1 and R2 represent a substituent having 1 to 8 carbon atoms; and (2) wherein R3 and R4 represent a substituent having 1 to 8 carbon atoms, may be the same as R1 and R2, and may be the same as each other.
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Page/Page column 69
(2008/06/13)
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- Method for preparing chiral diphosphines
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The invention concerns a method for preparing a compound of formula (1) wherein: A represents naphthyl or phenyl optionally substituted; and Ar1, Ar2independently represent a saturated or aromatic carbocyclic group, optionally substituted.
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- Asymmetric hydrogenation method of a ketonic compound and derivative
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The present invention relates to a process for the asymmetric hydrogenation of a ketonic compound and derivative. The invention relates to the use of optically active metal complexes as catalysts for the asymmetric hydrogenation of a ketonic compound and derivative. The process for the asymmetric hydrogenation of a ketonic compound and derivative is characterized in that the asymmetric hydrogenation of said compound is carried out in the presence of an effective amount of a metal complex comprising as ligand an optically active diphosphine corresponding to one of the following formulae: STR1
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- A regioselective synthesis of 4-methyl-1-pyrindan-5-one
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The enamine 7 reacts with crotonic aldehyde in the presence of p-toluenesulphonic acid via the intermediate 8 to yield regioselectively the unknown title compound 9. In alkaline medium, 9 is also formed from 7 and acetylacetaldehyde dimethyl acetal as well as small amounts of 11 and 12; under acidic conditions, however, mixtures of the regioisomers 9/9a are obtained in poor yield. 9a can be separated by fractional crystallisation of the hydrochlorides. Corresponding to 7 the homologous enamine 13 and acetylacetaldehyde acetal by alkaline catalysis gives the 4-methyltetrahydroquinolinone 1, respectively. Improved experimental details for an efficient preparation of the starting compounds 3 and 4 are given.
- Reimann,Poschl
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p. 589 - 592
(2007/10/02)
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- Inhibitors of the advanced glycosylation of proteins and methods of use therefor
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The present invention relates to compositions and methods for inhibiting nonenzymatic cross-linking (protein aging). Accordingly, a composition is disclosed which comprises an agent capable of inhibiting the formation of advanced glycosylation endproducts of target proteins by reacting with a carbonyl moiety of an early glycosylation product of such target proteins resulting from their initial glycosylation. The method comprises contacting the target protein with the composition. Both industrial and therapeutic applications for the invention are envisioned, as food spoilage and animal protein aging can be treated.
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- Process for the production of 1,3-cyclopentanedione
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A process for the production of 1,3-cyclopentanedione, which is a versatile intermediate product for numerous active ingredient syntheses. For this purpose, a malonic acid ester is reacted with a haloalkoxybutenoic acid ester, the resultant bis-(alkoxycarbonyl) alkoxypentenoic acid ester is cyclized to alkoxycarbonyl alkoxycyclopentenone, the ester function is saponified, and finally the intermediate is decarboxylated to the end product.
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- Mechanism of hydrolysis and structure-stability relationship of enaminones as potential prodrugs of model primary amines
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The objective of this work was to investigate the chemistry and the structure-stability relationship of enaminones (a class of enamines formed between a primary amine and a 1,3-dicarbonyl compound) and to evaluate their potential usefulness as prodrugs of primary amines. The acid-catalyzed degradation of the enaminones was found to be very sensitive to minor differences in the structure of the 1,3-dicarbonyl compound used to form the enaminone, but relatively insensitive to changes in the amine portion of the enaminones. A correlation was found between the rate of enaminone hydrolysis and the pK(a) of the 1,3-dicarbonyl compound, suggesting that the rate-controlling step in the hydrolysis of the enaminones was the proton addition to the vinyl carbon of the enaminone. Enaminones formed with cyclic 1,3-dicarbonyl compounds were significantly more stable than those formed with structurally similar acyclic compounds. Based on chemical stability considerations alone, enaminones do not appear to be good candidates as prodrugs of primary amines. Evidence is presented, however, that enaminones formed between amines and 1,3-ketoesters or lactones may be subject to enzyme-catalyzed degradation. Further research on the design of enaminones destabilized by a triggering enzymatic event that results in the loss of conjugation (e.g., ester or lactone hydrolysis or an oxidation/reduction event) may prove worth pursuing.
- Naringrekar,Stella
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p. 138 - 146
(2007/10/02)
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- REMOTE OXIDATION OF KETONES TO γ- AND δ-DIKETONES
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A single stage remote oxidation of ketones to γ- and δ-diketones has been carried out in a sodium peroxysulfate-iron(II) sulfate system.
- Troyanskii, E.I.,Mizintsev, V. V.,Lazareva, M. I.,Demchuk, D. V.,Nikishin, G. I.
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p. 1879 - 1884
(2007/10/02)
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- Palladium(0)-catalyzed isomerization of α,β-epoxy ketones to β-diketones
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In the presence of catalytic amounts of tetrakis(triphenylphosphine)palladium(0) and 1,2-bis(diphenylphosphino)ethane, α,β-epoxy ketones isomerize to the corresponding β-diketones in high yields.Both open-chain and cyclic substrates can be used.Possible reaction mechanisms are discussed.
- Suzuki, M.,Watanabe, A.,Noyori, R.
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p. 230 - 236
(2007/10/02)
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- Conversion of 3-Acetoxy-6-acetoxymethyl-2H-pyran-2-one to Cyclopentenone Derivatives and 1,3-Cylopentadienone
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Simple synthetic routes to 2-cyclopentenone derivatives and 1,3-cyclopentadienone from 3-acetoxy-6-acetoxymethyl-2H-pyran-2-one were developed.
- Tajima, Kiyohiko
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p. 1319 - 1322
(2007/10/02)
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- REGIOSELECTIVE REDUCTIONS OF 2,3-EPOXY ACETALS WITH ZINC-CHLOROTRIMETHYLSILANE AND LITHIUM ALUMINIUM HYDRIDE: CONVENIENT SYNTHESIS OF 1,2 AND 1,3-DIONES
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A variety of 2,3-epoxy acetals have been found to undergo regioselective reductions with zinc-chlorotrimethylsilane and lithium aluminium hydride to give 2-hydroxy and 3-hydroxy acetals respectively.Their oxidation followed by hydrolysis furnished the corresponding 1,2- and 1,3-diones in good yields.
- Vankar, Yashwant D.,Chaudhuri, Narayan C.,Rao, C. Trinadha
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p. 551 - 554
(2007/10/02)
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- DIRECT REMOTE OXIDATION OF ALIPHATIC KETONES TO γ- AND δ-DIKETONES
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Aliphatic ketones are converted into γ- and δ-diketones in onepot oxidation reaction on treatment with Na2S2O8 in presence of Fe(II)ions.
- Nikishin, Gennady I.,Troyansky Emmanuil I.,Lazareva, Margarita I.
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p. 4987 - 4988
(2007/10/02)
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- PHOTOLYSIS OF SATURATED BICYCLIC PEROXIDES
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Under direct photolysis (n.2.1)-peroxides (n=3-5) isomerise chiefly to epoxyaldehydes, (n.2.2)-peroxides (n=2-4) mainly undergo dehydrogenation to cycloalkane-1,4-diones, and 2,3-dioxabicyclo(2.2.1)heptane exhibits both types of behaviour; photo-isomerisation of 6,7- into 6,8-dioxabicyclooctane occurs when benzophenone is present as sensitiser.
- Bloodworth, A.J.,Eggelte, Henny J.
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p. 1525 - 1528
(2007/10/02)
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- A FACILE SYNTHESIS OF 1,3-CYCLOALKADIONES
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1,3-Cycloalkadiones were prepared by the reaction of 1,2-bis(trimethylsiloxy)cycloalkenes with chloromethyl methyl ether followed by treatment of the resulting 2-hydroxy-2-methoxymethyl cycloalkanones with potassium hydrogen sulfate.The first step of the reactions was effectively catalyzed by active zinc reagents prepared from zinc-copper and alkyl iodides.
- Nishiguchi, Ikuzo,Hirashima, Tsuneaki,Shono, Tatsuya,Sasaki, Manji
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p. 551 - 554
(2007/10/02)
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- 2-Hydrocinnampyl-1,3-cyclopentanediones
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As new compound, a series of 2-hydrocinnamoyl-1,3-cyclopentanedione derivative of the general formula: STR1 WHEREIN Ar stands for a mono-valent aromatic radical, for example, phenyl and 3,4-methylenedioxy-phenyl, substituted or unsubstituted, have been found to have an activity to inhibit the action of tyrosine hydroxylase and to be useful as hypotensive agent. These new compounds may be produced by condensing 2-acetyl-1,3-cyclopentanedione with an aromatic aldehyde of the formula Ar-CHO wherein Ar is as defined, according to Claisen-Schmidt condensation, followed by the hydrogenation of the condensation product obtained, or the new compounds may also be produced by reacting 2-acetyl-1,3-cyclopentanedione with an aromatic halide of the formula Ar-CH2 X wherein Ar is as defined and X is a halogen, for example, in liquid ammonia and in the presence of an alkali metal amide.
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