- Cobalt(II)-Catalyzed Reaction of Enolizable Aldehydes with Alkenes in the Presence of Dioxygen: The Role of Acyl Radical
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Complex cobalt(II) (1) catalyzes the reaction of enolizable aliphatic aldehydes and dioxygen with an electron-deficient alkene to afford the adducts 4 and 5, whereas the reaction with unactivated alkenes leads to the corresponding epoxides 6.These reactions are proposed to proceed via a common pathway involving acyl radicals.
- Punniyamurthy, T.,Bhatia, Beena,Iqbal, Javed
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- REACTION OF PHOSPHORUS TRICHLORIDE WITH CARBOXYLIC ACIDS
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The reaction of phosphorus trichloride with a number of monobasic carboxylic acids has been studied and the optimum ratio of reactants for the yield of acid chlorides has been established.Based on analysis and the data from 31P NMR spectroscopy of the phosphorus-containing products from this reaction it is shown that at 40-50 deg C a mixture of P-H acids having a predominant content of pyrophosphorous acid is formed.
- Valitova, L. A.,Popova, E. V.,Ibragimov, Sh. N.,Ivanov, B. E.
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- Effects of a forming process on the properties and structure of RANEY-Ni catalysts for the hydrogenation of 1,4-butenediol
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Three commercial Ni-Al alloys formed by a vacuum atomization method (NAV), atmospheric atomization method (NAA) and high-temperature melting method (NAH) were leached by 10 wt% NaOH solution to prepare three RANEY-Ni catalysts (RNAV, RNAA and RNAH, correspondingly). The effects of a forming process on the structure of Ni-Al alloys and the corresponding RANEY-Ni catalysts were investigated via XRD, XPS, SEM, TEM, NH3-TPD, N2 adsorption-desorption and EDX-mapping studies. Also, the as-prepared RANEY-Ni catalysts were evaluated via the hydrogenation of 1,4-butenediol (BED) to produce 1,4-butanediol (BDO). The results showed that the specific surface areas and surface morphologies of the Ni-Al alloys present significant differences. Meanwhile, the RNAA sample presented a comparatively regular morphology, similar to a small piece of sugar cane. The weak and medium acid peak areas of the RNAA catalyst were lower than those of the other samples. RNAV showed higher weak and medium acid peak areas, demonstrating the higher number of acid centers on the surface of the catalyst. The surface of the RNAA catalyst obtained from NAA contained more active component-Ni, about 90 wt% on the surface, and the specific surface area of the sample was 75 times that of its precursor Ni-Al alloy powder (NAA). The evaluation results present that the RNAA catalyst shows better hydrogenation performance, with BED conversion of 100%, both BDO selectivity and yield of 46.11%.
- Fan, Xing,Gao, Xianlong,Ma, Fengyun,Mo, Wenlong,Noritatsu, Tsubaki,Wu, Hongli
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- Development of triazine-based esterifying reagents containing pyridines as a nucleophilic catalyst
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We have developed new triazine-based esterifying reagents comprising pyridines that can act as a nucleophilic catalyst. 1-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-3,5-lutidinium chloride (DMT-3,5-LUT) was found to exhibit a superior reactivity for the dehydrating condensation reaction between carboxylic acids and alcohols. The reaction of DMT-3,5-LUT with carboxylic acids produces intermediacy of acyloxytriazines, which is known to exhibit moderate reactivity toward alcohols, with concomitant liberation of 3,5-lutidine. The subsequent chemical transformation of the acyloxytriazines and alcohols into esters can be accelerated by the action of 3,5-lutidine as a nucleophilic catalyst. The detailed reaction mechanism revealed by a time-course analysis of the reactions is also discussed.
- Yamada, Kohei,Liu, Jie,Kunishima, Munetaka
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supporting information
p. 6569 - 6575
(2018/09/25)
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- Study on 1,3,5-triazine chemistry in dehydrocondensation: Gauche effect on the generation of active triazinylammonium species
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The reaction of 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) with various nitrogen-containing compounds, particularly tertiary amines (tert-amines), has been studied for the preparation of 2-(4,6-dimethoxy-1,3,5-triazinyl) trialkylammonium salts [DMT-Am(s)]. DMT-Ams derived from aliphatic tert-amines exhibited activity for the dehydrocondensation between a carboxylic acid and an amine to form an amide in a model reaction. Based on a conformational analysis of DMT-Ams and tert-amines by NMR and X-ray diffraction methods, we concluded that a β-alkyl group maintained in a gauche relationship with the nitrogen lone pair of tert-amines significantly hinders the approach of CDMT to the nitrogen. Thus, trimethylamine and quinuclidine without such alkyl groups readily react with CDMT whereas triethylamine, possessing two or three such gauche β-alkyl groups in the stable conformations, does not react at all. The theory of "gauche β-alkyl group effect" proposed here provides useful guidelines for the preparation of DMT-Ams possessing various tertiary amine moieties. An investigation of the dehydrocondensation activity of tert-amines in a CDMT/tert-amine system that involves in situ generation of DMT-Am, showed that the gauche effect of the β-alkyl group becomes quite pronounced; the yield of the amide decreases significantly with tert-amines possessing an unavoidable gauche β-alkyl group. Thus, the tert-amine/CDMT systems are useful for judging whether tert-amines can readily react with CDMT without isolation of DMT-Ams. The right approach! The structure-activity relationship of nitrogen-containing compounds including aliphatic tertiary amines in the reaction with 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) has been investigated (see scheme). The theory of "gauche β-alkyl group effect" proposed here provides useful guidelines for the preparation of triazine-based dehydrocondensation reagents (DMT-Ams) possessing various tertiary amine moieties. Copyright
- Kunishima, Munetaka,Ujigawa, Takae,Nagaoka, Yoshie,Kawachi, Chiho,Hioki, Kazuhito,Shiro, Motoo
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p. 15856 - 15867
(2013/01/16)
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- Efficient and convenient synthesis of symmetrical carboxylic anhydrides from carboxylic acids with sulfated zirconia by phase transfer catalysis
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An efficient and convenient procedure for the synthesis of symmetrical carboxylic anhydrides from carboxylic acids with sulfated zirconia by PEG-1000 phase transfer catalysis has been developed. The reactions proceeded under mild and solvent-free conditions to provide the carboxylic anhydrides in good to excellent yields. The product can be isolated by a simple extraction with organic solvent, and the catalyst system can be recycled or reused without any significant loss of catalytic activity.
- Hu, Yu Lin,Zhao, Xing E.,Lu, Ming
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experimental part
p. 255 - 262
(2012/04/17)
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- CASPASE INHIBITORS AND USES THEREOF
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This invention provides novel caspase inhibitors useful for prophylaxis or treatment of a number of pathologies, including, for example, Huntington's disease. In certain embodiments the inhibitors include inhibitors of casepase-3 and/or casepase-6.
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Page/Page column 27
(2010/04/03)
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- Ruthenium-Catalyzed Oxidative Cleavage of Alkynes to Carboxylic Acids
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We describe an efficient method for the oxidative cleavage of alkynes to carboxylic acids using a combination of RuO2/Oxone/NaHCO3 in a CH3CN/H2O/EtOAc solvent system. Both internal and terminal alkynes, regardless of their electron density, can be oxidized to carboxylic acids in excellent yield (up to 99%). 1H NMR spectroscopy and ESI-MS experiments provided evidence for α-diketones and anhydrides as possible intermediates in these oxidation reactions.
- Yang, Dan,Chen, Fei,Dong, Ze-Min,Zhang, Dan-Wei
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p. 2221 - 2223
(2007/10/03)
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- Method for preparing a benzylic-type ether
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The invention concerns a method for preparing a benzylic-type ether from an aromatic compound. The inventive method for preparing a benzylic-type ether from an aromatic compound is characterised in that it consists in: in a first step, acylating an aromatic compound by reacting said aromatic compound with an acylating agent, in the presence of an efficient amount of zeolite or a Friedel-Crafts catalyst leading to a ketonic compound; in a second step, reducing the carbonyl group into carbinol leading to a benzylic alcohol; in a third step, etherifying the hydroxyl group, by reacting the benzylic alcohol with another alcohol, in the presence of an efficient amount of zeolite.
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- Acylation method for an aromatic compound
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The present invention concerns a process for acylation of an aromatic compound.The acylation process of the invention consists of reacting the aromatic compound with an acylation agent in the presence of a zeolitic catalyst, and is characterized in that it consists of:mixing the aromatic compound and the acylation compound in any manner;passing said mixture over a catalytic bed comprising at least one zeolite;recirculating the reaction mixture from the catalytic bed over the catalytic bed for a number of times which is sufficient to obtain the desired degree of conversion of the substrate.
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- A search for quantitative acylation of α-trinositol (1D-myo-inositol 1,2,6-tris(dihydrogen phosphate) pentasodium salt)
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The acylation of α-trinositol is very sensitive to reaction conditions. Competing condensation reactions may give pyrophosphates and cyclic phosphates. Treatment of a tert-ammonium salt corresponding to α-trinositol with carboxylic acid anhydride and DMAP gives a good yield of the expected esters.
- Malmberg, Mats,Rehnberg, Nicola
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p. 459 - 464
(2007/10/03)
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- Cobalt(II)-Catalyzed Reaction of Aldehydes with Acetic Anhydride under an Oxygen Atmosphere: Scope and Mechanism
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The reaction of aldehydes with acetic anhydride in the presence of catalytic cobalt(II) chloride under an oxygen atmosphere at ambient temperature is dependent upon the reaction medium.Aliphatic aldehydes react in acetonitrile to give 1,2-diones whereas the aromatic aldehydes are acylated to yield the corresponding acylals.On the other hand, carboxylic acids are obtained from aliphatic and aromatic aldehydes by conducting the reaction in dichloroethane or benzene.Cobalt(II) chloride in acetonitrile catalyzes the conversion of aliphatic aldehydes to the correspondinganhydrides in the absence of acetic anhydride whereas aromatic aldehydes remain largely unaffected under these conditions.A preliminary mechanistic study in three different solvents (i.e. acetonitrile, dichloroethane, and DMF) has revealed that in acetonitrile and in the presence of acetic anhydride, aliphatic aldehydes behave differently than aromatic aldehydes.Some trapping experiments using methyl acrylate and stilbene have been conducted to demonstrate the occurence of an acyl cobalt and peroxyacyl cobalt intermediate during these reactions.
- Bhatia, Beena,Punniyamurthy, T.,Iqbal, Javed
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p. 5518 - 5523
(2007/10/02)
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- COBALT(II) CHLORIDE CATALYZED SYNTHESES OF ACID ANHYDRIDES FROM ACID CHLORIDES
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Acid anhydrides were synthesized by reacting acid chlorides with carboxylic acids in the presence of catalytic quantities of cobalt(II) chloride.
- Srivastava, Rajiv R.,Kabalka, George W.
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p. 593 - 594
(2007/10/02)
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- Derivatives from 3,4-dehydro-piperidin-5-one exhibiting a herbicidal activity
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The present invention relates to derivatives of 3,4-dehydropiperidin-5-one having herbicidal activity. The derivatives have the formula STR1 as defined in the claims. The present invention further relates to a herbicidal composition and a method for controlling weeds which grow among agricultural crops.
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- Hydroxy protection groups
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The present invention concerns a method for preparing unprotected hydroxy compounds or acylated derivatives thereof by conversion of silyl alkyl-protected hydroxy compounds. The invention also relates to novel intermediates useful in the method and for other purposes.
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- 2-OXY-4H-3,1-BENZOXAZIN-4-ONES AND PHARMACEUTICAL USE
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2-Oxy-4H-3,1-benzoxazin-4-ones represented by the formula: STR1 and the pharmaceutically acceptable acid addition salts thereof, wherein: a is an integer of 0-4;A is a bond, or alkylene having one to eight carbon atoms;R is hydrogen, phenyl, imidazolyl or cycloalkyl having three to six carbon atoms, wherein the phenyl, imidazolyl or cycloalkyl ring is optionally substituted with 1-3 substituents independently selected from the group consisting of lower alkyl having one to four carbon atoms, lower alkoxy having one to four carbon atoms,--N(R 1) 2,--NO 2, halo or lower alkylthio having one to four carbon atoms, and, each R' is independently selected from the group consisting of lower alkyl having one to six atoms, lower alkenyl having two to six carbon atoms, lower alkoxy having one to six carbon atoms, lower alkylthio or halo-lower alkyl having one to four carbon atoms, halo,--NO 2,--N(R 1) 2, STR2--NR 1 COR 2, and STR3 in which each R 1 is independently hydrogen or lower alkyl having one to four carbon atoms, or together form a piperidine or a piperazine ring optionally substituted at the ring nitrogen by lower alkyl having one to four carbon atoms or--CH 2 CH 2 OH, each R 2 is independently lower alkyl having one to four carbon atoms, A is an alkylene group if R is hydrogen, and the pharmaceutically acceptable acid addition salts thereof are useful as serine protease inhibitors in humans and animals.
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- Optical brightening agents of naphthalimide derivatives
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A naphthalimide derivative having the formula STR1 wherein R is an alkyl, or cycloalkyl, an aralkyl, a haloalkyl, an alkoxyalkyl, a hydroxyalkyl, an N,N-dialkylaminoalkyl, an unsubstituted or halogen-, alkyl-, alkoxy- or hydroxy-substituted aryl, or an ammoniumalkyl; X is a group of the formula, STR2 wherein A is STR3 or an unsubstituted or halogen-substituted arylene, or a group of the formula, STR4 wherein R1 is hydrogen, an alkyl, phenyl, a hydroxyalkyl, or an alkoxyalkyl; Y is --CO--, --COO--, --CONR3 -- (where R3 is hydrogen or an alkyl), or --SO2 --; R2 is hydrogen, an alkyl, a cycloalkyl, an aralkyl, a haloalkyl, an alkyl- or aryl-substituted amino-alkyl, an unsubstituted or halogen-, alkyl-, alkoxy-, hydroxy-, amino- or alkylamino-substituted aryl, a group of the formula, STR5 (where R, R1 and Y are as defined above and R4 is a bivalent group), or a group of the formula, (where R5 is direct linkage or a bivalent group; Q+ is a substituted ammonium, a cycloammonium or a hydrazinium; and α- is an anion), Which is useful for optically brightening an organic polymer material.
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