- CH3COONa as an effective catalyst for methoxycarbonylation of 1,6-hexanediamine by dimethyl carbonate to dimethylhexane-1,6-dicarbamate
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Methoxycarbonylation of 1,6-hexanediamine (HDA) by dimethyl carbonate (DMC) was carried out, using, for the first time, CH3COONa as catalyst. The effects of the solvent, reaction temperature, reaction time, and catalyst amount, were investigated. A yield as high as 99.0% of dimethylhexane-1,6- dicarbamate 2 has been obtained at a temperature of 348 K and a reaction time of 6 h. Mechanistic studies revealed that N-substituted acetamide, as the active intermediate product, and NaOH were first formed via the reaction between HDA and CH3COONa. A further reaction between the N-substituted acetamide and DMC generated carbamates and methyl acetate, via a hexatomic ring intermediate. The CH3COONa catalyst was finally recovered through the reaction between NaOH and methyl acetate, which thus completed the catalytic cycle.
- Sun, Da-Lei,Xie, Shun-Ji,Deng, Jian-Ru,Huang, Cai-Juan,Ruckenstein, Eli,Chao, Zi-Sheng
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Read Online
- Synthesis of dimethyl carbonate by urea alcoholysis over Zn/Al bi-functional catalysts
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Zn/Al mixed oxides (ZAO) were prepared via thermal decomposition of hydrotalcite-type precursors derived from urea precipitation. Specially, ZAO catalysts with a Zn/Al molar ratio of 4:1 exhibited high dimethyl carbonate (DMC) yield (~36.5%) when utilized for the DMC synthesis from urea and methanol. The XRD, IR, TPD and computational analysis revealed that the formation of ZnAl2O4 spinel significantly modified the surface acidity and basicity of ZAO catalysts, which were beneficial for the DMC synthesis. We thus opened up a bi-functional mechanism that urea and methanol were respectively activated on the weak acidic and basic sites, advancing the DMC synthesis synergistically.
- Wu, Xiaomin,Kang, Min,Yin, Yanlong,Wang, Feng,Zhao, Ning,Xiao, Fukui,Wei, Wei,Sun, Yuhan
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Read Online
- Synthesis of dimethyl carbonate from methanol and urea over zinc-strontia mixed oxide catalysts
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A series of ZnO-SrO mixed oxide catalysts were prepared by co-precipitation with different compositions and tested for dimethyl carbonate synthesis from urea and methanol. The catalysts were characterized by BET surface area, XRD, NH3-TPD and CO2-TPD. The catalyst with 1:1 mol ratio exhibited high DMC yield of 35%. The uniform distributions of moderate to strong basic sites along with considerable number of acidic sites are accountable for high activity. Different reaction parameters were also screened and best possible conditions were established. The catalyst was easily recovered and reused with consistent activity.
- D., Dhana Lakshmi,B., Srinivasa Rao,Lingaiah
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Read Online
- One-pot efficient synthesis of methyl carbamate by M5Ca5(PO4)6F2 (M?=?Co, Ni, Cu, Zn) catalysts
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A facile and efficient one-pot synthesis of methyl carbamate (MC) by urea and methanol was studied using metal modified fluorapatite as a catalyst. M5Ca5(PO4)6F2 (M5FAP, M = Co, Ni, Cu, Zn) was synthesized by co-precipitation. Among the catalysts, Zn5Ca5(PO4)6F2 (Zn5FAP) displayed the higher activity, selectivity and excellent stability after five times of reuse. A possible synthesis reaction mechanism over Zn5FAP catalyst was discussed.
- Wang, Wei,Xu, Feng,Du, Wenqiao,Zhang, Long
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Read Online
- Dimethyl carbonate synthesis over ZnO-CaO bi-functional catalysts
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ZnO-CaO catalysts were prepared and tested for the synthesis of dimethyl carbonate (DMC) from urea and methanol. Meaningfully, the bi-functional catalysts ZnO-CaO exhibited noticeable DMC yield (41.2%) with the Zn/Ca molar ratio of 4:1, which might ascribe to the synergistic effect between ZnO and CaO. The plausible mechanism for the DMC synthesis was as follows: urea was activated to generate metal isocyanato group on the acid sites and subsequently nucleophilic attacked by the activated methanol on the basic sites.
- Wu, Xiaomin,Kang, Min,Zhao, Ning,Wei, Wei,Sun, Yuhan
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Read Online
- Preparation method of carbamate
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The invention belongs to the technical field of synthesis of amino and carboxyl compounds connected to the same carbon frame through urea alcoholysis, and particularly relates to a preparation methodof carbamate. The preparation method of the carbamate comprises the following steps of: sequentially introducing urea, alcohol and a catalyst into a reactor, sealing, and reacting at 90-120 DEG C for8-12 hours to obtain the carbamate, wherein the catalyst includes an alumina supported metal oxide. By adopting the method for preparation of the carbamate, the side reaction of urea decomposition canbe effectively avoided, impurities such as carbamate are not detected, and the yield of the carbamate is high.
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Paragraph 0034; 0038-0040
(2020/09/23)
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- Carbamate preparation method
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The invention relates to a carbamate preparation method. According to the invention, dimethyl carbonate is used as a reaction raw material for urea alcoholysis, and a novel composite catalyst is used,so that the technical problems of high energy consumption and high equipment cost caused by cold energy ammonia removal in the prior art are avoided, and the yield of carbamate is up to more than 96%.
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Paragraph 0026-0046
(2020/03/12)
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- Method for directly preparing dimethyl carbonate through reaction of low-temperature high-efficiency catalytic urea and methanol (by machine translation)
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The invention relates to a method for directly preparing dimethyl carbonate through reaction of urea and methanol at low temperature, and a method for directly preparing dimethyl carbonate by using the high-efficiency solid-phase Mg - Ga catalyst. 2 O3 /CeO2 - Al2 O3 The, method has the advantages that the yield of, dimethyl carbonate can be further improved, the, reaction activity and, selectivity are high, 100%, the conversion rate of the by-product is lower than that of dimethyl carbonate, and the selectivity of dimethyl carbonate to dimethyl carbonate is greater than or equal to and equal to or greater than or equal to and equal. 99.2% to or greater than about. (by machine translation)
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Paragraph 0047; 0050-0052; 0054
(2020/02/05)
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- Method for producing methyl carbamate
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The invention provides a method for producing methyl carbamate. The method comprises the following steps: performing sectional temperature control on an exhaust channel of a reaction kettle, controlling the temperature of a pipeline section of the exhaust channel close to the reaction kettle to 4-20 DEG C, and increasing the temperatures of later pipeline sections gradually till the temperature ofa pipeline section of the exhaust channel far away from the reaction kettle is 75-85 DEG C; and performing pressurization on a reaction process for preparing methyl carbamate by using a urea alcoholysis method to release a gas, and maintaining the pressure of the reaction system in the reaction kettle to 1.8-2.8MPa. By adopting the method, the technical problem that the exhaust channel of the reaction kettle is blocked can be solved, industrial conditions of production of methyl carbamate can be completed, production reactions can be performed smoothly, and in addition, the yield of the methyl carbamate can be increased.
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Paragraph 0018-0024
(2019/12/31)
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- Method for preparing methyl carbamate by taking urea as raw material
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The invention belongs to the technical field of preparation of compounds containing amino and carboxyl connected to a same carbon frame from natural products, and particularly relates to a method forpreparing methyl carbamate by taking urea as a raw material. The preparation method of the methyl carbamate comprises the following steps: sequentially introducing urea, methanol and a catalyst into areactor, sealing, and reacting at 130 to 150 DEG C for 4-6 hours to obtain the methyl carbamate, wherein the catalyst comprises titanium dioxide-bismuth oxide supported by silicon dioxide. The content of impurities such as methyl carbamate analogues is low, and the yield of methyl carbamate is high.
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Paragraph 0027-0029
(2019/12/25)
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- An Fe3O4@SiO2/Schiff base/Cu(ii) complex as an efficient recyclable magnetic nanocatalyst for selective mono: N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids
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An efficient, convenient and novel method for the selective mono N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids in the presence of a recyclable magnetic Cu(ii) nanocatalyst is described. A variety of mono N-arylated O-alkyl thiocarbamates and O-alkyl carbamates were prepared in good to excellent yields with a broad range of aryl coupling partners. The magnetic nanocatalyst can be easily recovered with an external magnetic field and reused at least five times without noticeable leaching or loss of its catalytic activity. This cost-effective and eco-friendly methodology has some other advantages, such as easy preparation of the catalyst, simple workup procedure, and easy purification, which makes this protocol interesting for the users in various fields of pharmacology and biotechnology systems.
- Sardarian, Ali Reza,Dindarloo Inaloo, Iman,Zangiabadi, Milad
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p. 8557 - 8565
(2019/06/14)
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- Method for preparing methyl carbamate by urea methanolysis method
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The invention provides a method for preparing methyl carbamate by a urea methanolysis method. The method comprises the following steps of adding methyl alcohol and urea into a high-pressure reaction kettle which is provided with a magnetic stirrer and a heating temperature control system, stirring for 20min at the temperature of 30 DEG C, and fully mixing; then, adding a catalyst Ni5Ca5(PO4)6F2, sending CO2 (carbon dioxide) into the reaction kettle for three times, replacing the air in the reaction kettle, and reacting for 2-10h at the CO2 pressure of 0.6MPa and the temperature of 120-170 DEG C in the reaction kettle, wherein the total mass ratio of the catalyst Ni5Ca5(PO4)6F2 and the reactants of urea and methyl alcohol is 1-5:100, and the molar ratio of methyl alcohol and urea is 15:1; lowering the temperature of the reaction system to the room temperature, filtering and removing the catalyst, and rotationally evaporating the methyl alcohol, so as to obtain a target product of methyl carbamate. The selectivity of the obtained methyl carbamate is 98.9%, the conversion rate of urea is 99.8%, and the maximum yield of methyl carbamate is 98.8%. The method for preparing the methyl carbamate has the characteristics that the preparation technology is simple, the reaction condition is mild, the yield of the target product is high, and the like; the method is a clean methyl carbamate preparation technology.
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Paragraph 0008
(2017/04/03)
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- Process method of co-production of oxamide and carbamic acid ester through ammonia ester exchange method
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The invention discloses a process method of co-production of oxamide and carbamic acid ester through an ammonia ester exchange method. According to the process method, urea and oxalic acid diethyl serve as raw materials, and two products, namely the oxamide and the carbamic acid ester, can be obtained at the same time through a series of ammonia ester exchange reactions. By means of the process, the problems that products are singular, and by-products affect the reaction process in an original technology for synthesizing oxamide through oxalic acid diethyl ammonolysis and a technology for synthesizing carbamic acid ester through urea alcoholysis are solved; besides, due to the fact that urea is obtained through CO and NH synthesis, NH is replaced with urea, and the process method has active significance in converting CO into high added-value chemicals and efficiently utilizing CO.
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Paragraph 0034; 0035
(2016/10/08)
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- PROCESS FOR THE SYNTHESIS OF DIMETHYLCARBONATE
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The present invention discloses a process for the synthesis of dimethyl carbonate (DMC) and further methyl-N-methyl carbamate (MNMC) starting from urea or methyl carbamate using salts such as nitrate or triflate salts of rare earth elements, transition metals, alkaline earth and alkali metals as catalysts.
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Page/Page column 17
(2015/11/02)
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- 4-Dodecylbenzenesulfonic acid (DBSA) promoted solvent-free diversity-oriented synthesis of primary carbamates, S-thiocarbamates and ureas
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A simple and highly efficient solvent-free method for the conversion of alcohols, phenols, thiols and amines to primary carbamates, S-thiocarbamates and ureas in the presence of 4-dodecylbenzenesulfonic acid (DBSA) as a cheap and green Bronsted acid reagent has been described. All products were obtained in good to excellent yields and characterized using FT-IR, 1H- and 13C-NMR, MS and CHNS techniques.
- Sardarian, Ali Reza,Inaloo, Iman Dindarloo
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p. 76626 - 76641
(2015/09/22)
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- Catalytic alcoholysis of urea to diethyl carbonate over calcined Mg-Zn-Al hydrotalcite
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The synthesis of diethyl carbonate (DEC) from urea and ethanol was carried out over Mg-Zn-Al composite oxide catalysts derived from hydrotalcites (HTs). The catalytic results showed that the ternary hydrotalcites calcined at 450 °C with Mg:Zn:Al = 1:1.7:1 exhibited superior catalytic activity, and the highest DEC yield was 67.8%. Similar to ethanol, other alcohols such as methanol and butanol can also be transformed to corresponding dialkyl carbonates. Catalysts were characterized by XRD, BET, SEM and TPD with the aim of establishing a relationship between performance and structure. The results indicated that MgZn1.7Al-450 with nanoplate morphology and more accessible active medium basic sites were favourable for obtaining much superior catalytic activity. Recycling experiments demonstrated that the catalyst could be successfully reused. This journal is
- Wang, Peixue,Liu, Shimin,Zhou, Feng,Yang, Benqun,Alshammari, Ahmad S.,Deng, Youquan
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p. 19534 - 19540
(2015/06/15)
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- SYNTHESIS OF METHYL CARBAMATE AND DIMETHYL CARBONATE (DMC) IN PRESENCE OF STRIPPING WITH INERT GAS OR SUPERHEATED VAPOURS AND A REACTOR FOR THE SAME
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The invention relates to synthesis of methyl carbamate (MC) and dimethyl carabonate (DMC) in presence of stripping inert gas or superheated methanol vapors using packed column reactor and bubble column reactor.
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Page/Page column 21
(2014/05/24)
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- SYNTHESIS OF DIMETHYL CARBONATE AND RELATED COMPOUNDS
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An improved process for synthesis of dimethyl carabonate (DMC) and related compounds further, starting from urea or methyl carbamate and methanol employing novel catalysts, double metal cyanides, cenospheres, hydrotalcites and hydrotalcite like compunds.
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Page/Page column 18
(2014/05/24)
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- Organic carbonate synthesis from CO2 and alcohol over CeO 2 with 2-cyanopyridine: Scope and mechanistic studies
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The combination system of CeO2-catalyzed carboxylation and 2-cyanopyridine hydration (CeO2 + 2-cyanopyridine system) is effective for the direct synthesis of organic carbonates from CO2 and alcohols. This catalyst system can be applied to various alcohols to afford the corresponding carbonates in high alcohol-based yields. The hydration of 2-cyanopyridine over CeO2 rapidly proceeds under the low concentration of water, which can remove the water from the reaction media. Since the reaction is limited by the chemical equilibrium, the removal of water remarkably shifts the chemical equilibrium to the carbonate side, leading to high carbonate yields. In addition, 2-picolinamide that is produced by hydration of 2-cyanopyridine forms an intramolecular hydrogen bonding between H atom of the amide group and N atom of the pyridine ring, which weakens the adsorption of 2-picolinamide on CeO2 by reduction of the acidity. The reaction mechanism of DMC formation in CeO2 + 2-cyanopyridine system is also proposed.
- Honda, Masayoshi,Tamura, Masazumi,Nakagawa, Yoshinao,Nakao, Kenji,Suzuki, Kimihito,Tomishige, Keiichi
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- CATALYST FOR THE SYNTHESIS OF ALKYL CARBAMATES, THE METHOD FOR PREPARING THE SAME AND THE USE THEREOF
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The present invention pertains to a catalyst for the synthesis of organic alkyl carbamates, the method for preparing the same and the use thereof. The catalyst comprises a catalytically active component and a catalyst support, and the catalytically active component being carried by the catalyst support, wherein the catalytically active component comprises a transition metal oxide, and the general formula of the transition metal oxide is EOx, wherein E is selected from transition metal element and x is in the range of 0.5-4.
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Page/Page column 4
(2011/07/08)
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- New attempt for CO2 utilization: One-pot catalytic syntheses of methyl, ethyl and n-butyl carbamates
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The direct production of methyl, ethyl and n-butyl carbamates (MC, EC and BC) from NH3, CO2 and alcohols could efficiently be catalyzed by V2O5, and ca. 11-25% yields with 98% selectivity for alkyl carbamates could be obtained. The catalyst could be recycled six times without obvious decrease in catalytic activity. XRD and XPS analysis showed that in-situ produced (NH4)2V 3O8 was the catalytically active species.
- Li, Jian,Qi, Xiujuan,Wang, Liguo,He, Yude,Deng, Youquan
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experimental part
p. 1224 - 1227
(2012/01/13)
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- CATALYST FOR THE SYNTHESIS OF ORGANIC CARBONATES, PROCESS FOR PREPARING THE SAME AND APPLICATION THEREOF
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The present invention relates to a catalyst for the synthesis of organic carbonates, the preparation of the catalyst and the application of this catalyst in the synthesis of organic carbonates from reacting urea and hydroxyl group containing compounds. The catalyst provided in this invention is a calcinate of hydrous salt containing rare earth element at a moderate calcining temperature.
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Page/Page column 3
(2010/12/29)
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- METHOD FOR PRODUCING CARBAMIC ACID ESTERS
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The invention relates to a method for producing carbamic acid esters during which urea or a urea derivative is, in a first stage, reacted with a polymeric multi-functional alcohol such as a polyalkylene glycol, a polyester polyol or a polyether polyol of general formula (I) in which R represents a straight-chain or branched alkylene group with 2 to 12 carbon atoms and n is a number between 2 and 20, or is reacted with a completely or partially hydrolyzed polyvinyl alcohol of general formula (II), in which R' represents an alkyl group, aryl group or acyl group with 1 to 12 carbon atoms, and p and q are numbers between 1 and 20, or is reacted with mixtures of these compounds without or in the presence of a catalyst, which promotes the cleavage of ammonia, whereby forming a carbamic acid ester of the mixture containing the aforementioned polymeric alcohols. At the same time, freely emerging ammonia or the amine is/are removed from the reaction mixture by a stripping gas and/or vapor and/or vacuum. In a second stage (transesterification), the mixture containing the carbamic acid esters of the polymeric alcohols is reacted with a monomeric alcohol or with a phenol while forming carbamic acid esters thereof and forming back the polymeric alcohols of formulas (I) or (II). The carbamic acid ester is subsequently obtained from the mixture in pure form while using a known method.
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Page/Page column 5-6
(2010/10/20)
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- Functional group transformation of perfluoroadamantane derivatives
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An adamantane skeleton, having rigid structure, has been used for a thermally stable and/or anti-etching material. It is expected to be a material having good optical properties, if fluorine atoms are introduced into the skeleton. Thus, the investigation concerning the functional group transformation of perfluoroadamantanecarboxylic acid derivatives was performed to develop the methods for introduction of perfluoroadamantyl group into molecules. Their unique reactivities are also discussed.
- Murata, Koichi,Wang, Shu-Zhong,Morizawa, Yoshitomi,Oharu, Kazuya
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p. 1125 - 1129
(2008/09/16)
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- Anti-cancer agents and uses thereof
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The present invention is in the area of novel compounds and salts thereof, their syntheses, and their use as anti-cancer agents. The compounds include compounds of Formula I: and solvates, hydrates and pharmaceutically-acceptable salts thereof, wherein A1 is N or CR1; A3 is N or CR3; A5 is N or CR5; R1, R3—R6 and L are defined in the specification; n is 0 or 1; and X is an optionally-substituted aryl group having 6-10 carbons in the ring portion, an optionally-substituted 6-membered heteroaryl group having 1-3 nitrogen atoms in the ring portion, an optionally-substituted 5-membered heteroaryl group having 0-4 nitrogen atoms in the ring portion and optionally having 1 sulfur atom or 1 oxygen atom in the ring portion, or an optionally-substituted heteroaryl group in which a 6-membered ring is fused either to a 5-membered ring or to a 6-membered ring, wherein in each case 1, 2, 3 or 4 ring atoms are heteroatoms independently selected from nitrogen, oxygen and sulfur. They are effective against a broad range of cancers, especially leukemia, non-small cell lung and colon.
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Page/Page column 48
(2008/06/13)
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- Process for making dialkyl carbonates
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A process for the production of dialkyl carbonates from the reaction of alcohol, for example C1-C3 alcohols, with urea is disclosed wherein the water and ammonium carbamates impurities in the feed are removed in a prereactor. The water is reacted with urea in the feed to produce ammonium carbamate which is decomposed along with the ammonium carbamates originally in the feed to ammonia and carbon dioxide. In addition some of the urea is reacted with the alcohol in the first reactor to produce alkyl carbamate which is a precursor to dialkyl carbonate. Dialkyl carbonates are produced in the second reaction zone. The undesired by-product N-alkyl alkyl carbamates are continuously distilled off from the second reaction zone along with ammonia, alcohol and dialkyl carbonates under the steady state reactor operation. N-alkyl alkyl carbamates can be converted to heterocyclic compounds in a third reaction zone to remove as solids from the system.
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Page/Page column 10
(2008/06/13)
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- 2-OXY-BENZOXAZINONE DERIVATIVES FOR THE TREATMENT OF OBESITY
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The use of a compound comprising formula (I): (I) or a salt, ester, amide or prodrug therof in the inhibition of an enzyme whose preferred mode of action is to catalyse the hydrolysis of an ester functionality, e. g. in the control and inhibition of unwanted enzymes in products and processes. The compounds are also useful in medicine e.g. in the treatment of obesity and related conditions. The invention also relates to novel compounds within formula (I), to processes for preparing them and pharmaceutical compositions containing them. In formula (I) A is a 6-membered aromatic or heteroaromatic ring; and R1 is a branched or unbranched alkyl (optionally interrupted by one or more oxygen atoms), alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, arylalkyl, reduced arylalkyl, arylalkenyl, heteroaryl, heteroarylalkyl, heteroarylalkenyl, reduced aryl, reduced heteroaryl, reduced heteroarylalkyl or a substituted derivative of any of the foregoing groups.
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- Method for reducing intraocular pressure using indole derivatives
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The present invention provides a method of reducing intraocular pressure by administering pharmaceutical compositions comprising indole derivatives. The pharmaceutical compositions useful in this invention comprise indole derivatives and melatonin analogs of Formulae I-IV. A preferred embodiment is a method of lowering intraocular pressure using 5-(methoxycarbonylamino)-N-acetyltryptamine (5-MCA-NAT), also known as GR 135531, which has a prolonged duration of action and greater efficacy in lowering intraocular pressure compared to melatonin. The present invention further provides a method of treating disorders associated with ocular hypertension, and a method of treating various forms of glaucoma; the method comprises administering an effective dose of a pharmacuetical composition comprising an indole derivative with or without agents commonly used to treat such disorders.
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- Process for S-Aryl cysteine
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The present invention provides methods for preparing S-aryl cysteines in enantiomeric excess of greater than about 96%. Specifically, the present invention provides enantioselective methods for preparing S-aryl cysteines starting from cystine, cysteine or
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- Anthranilic acid derivatives as multi drug resistance modulators
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Anthranilic acids of formula (I): wherein each of R to R9is an organic substituent, n is 0 or 1, m is 0 or an integer of 1 to 6, q is 0 or 1, X is a direct bond, O, S, —S—(CH2)por —O—(CHO2)p— wherein p is from 1 to 6 and Ar is an unsaturated carbocyclic or heterocyclic group, and the pharmaceutically acceptable salts thereof, have activity as inhibitors of P-glycoprotein and may thus be used, inter alia, as modulators of multidrug resistance in the treatment of multidrug resistant cancers, for example to potentiate the cytotoxicity of a cancer drug.
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- Efficient synthesis of a 1,4-dihydro2H-3,1-benzoxazin-2-one
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An efficient method for the preparation of a compound of (-)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl- 1,4-dihydro-2H-3, 1-benzoxazin-2-one, also known as DMP-266, a reverse transcriptase inhibitor is achieved using a cyclization reaction of the amino alcohol intermediate with an alkyl or aryl chloroformate and a base.
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- Process for producing 2,4-oxazolidinedione
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Provided is a process which comprises reacting a 2-hydroxycarboxylic acid ester with urea to form a 2,4-oxazolidinedione , separating an unreacted 2-hydroxycarboxylic acid ester and a catalyst from the resulting reaction solution through distillation, and purifying the fraction composed mainly of the 2,4-oxazolidinedione through crystallization and/or extraction. In accordance with the present invention, the purified 2,4-oxazolidinedione is easily produced in a high yield by a simple purification method without using a costly alkali metal compound.
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- Method for preparation of carbamates
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A method of preparing carbamates by reacting amine with alcohol and mixed gas of CO/O 2 in the presence of one or more catalyst selected from the group consisting of monovalent copper halide having the structural formula of Cu[NCMe 4 ]X, K[CuX 2 ], [CuX(S)] (wherein X=Cl, Br, or I; S=solvent) or monovalent copper compound having carbonyl group having the structural formula of [Cu(CO)X a L b ] m Y n (wherein, X=CF 3 CO 2, Cl, HB(pz) 3 (wherein, pz=pyrazoyl,C 3 H 3 N 2), LBF 2, {LBF 2 =difluoro-3,3''-(trimethylenedinitrilo)bis(2-butanone oximato)borate}; L=en, diene; Y=BPh 4, AsF 6 ; a,b=0,1; m=1-4; n=0,1).
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- Mechanisms of decomposition of aryl N-(methoxycarbonyl) sulfmates in aqueous media
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Rate constant and products are reported for the decomposition of aryl N- (methoxycarbonyl)sulfamates 1a-h (range) in aqueous solutions (pH 0-14) at 50 °C. The pK(a) values at 25 °C of 1a-h are 0.46-2.40. The pH-rate profiles of 1 indicate a rate law that includes three terms: two pH independent terms, k(a) in acid and k(p) around neutral pH, with k(a) > k(p), and a hydroxide ion dependent term, k(OH). In acid, product analysis reveals that both S-O (k(S02) and C - O (k(CO) bond cleavage reactions are involved. From an analysis of β(1g), solvent isotope effects, and solvent isotopic labeling of the products, it is concluded (a) that the C-O cleavage reaction involves protonation of the leaving group methanol and its expulsion from the dipolar intermediate ArOS02N-CO-O+HCH3 and (b) that the S-O cleavage reaction may involve either an intra- or an intermolecular general acid-catalyzed decomosition of 1 or 1-, respectively. In contrast to k(a), the spontaneous hydrolysis reaction of 1-, k(p), takes place exclusively via S-O bond fission. The k(OH) reaction of 1- is rationalized by OH- attack either at the carbonyl center (1b-h) or at the aromatic ring (1a). It is concluded that the -SO2NHCO-group may be viewed as an attractive phosphate analogue.
- Blans, Patrick,Vigroux, Alain
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p. 9574 - 9583
(2007/10/03)
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- Dynemicin analogs: syntheses, methods of preparation and use
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A fused ring system compound is disclosed that contains an epoxide group on one side of the fused rings and an enediyne macrocyclic ring on the other side of the fused rings. The compounds have DNA-cleaving, antimicrobial and tumor growth-inhibiting properties. Chimeric compounds having the fused ring system compound as an aglycone bonded to (i) a sugar moiety as the oligosaccharide portion or (ii) a monoclonal antibody or antibody combining site portion thereof that immunoreacts with target tumor cells are also disclosed. Compositions containing a compound or a chimer are disclosed, as are methods of preparing a compound.
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- Dynemicin analogs: synthesis, methods of preparation and use
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A fused ring system compound is disclosed that contains an epoxide group on one side of the fused rings and an enediyne macrocyclic ring on the other side of the fused rings. The compounds have DNA-cleaving, antimicrobial and tumor growth-inhibiting properties. Chimeric compounds having the fused ring system compound as an aglycone bonded to (i) a sugar moiety as the oligosaccharide portion or (ii) a monoclonal antibody or antibody combining site portion thereof that immunoreacts with target tumor cells are also disclosed. Compositions containing a compound or a chimer are disclosed, as are methods of preparing a compound.
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- Butenoic or propenoic acid derivatives
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A butenoic or propenoic acid derivative having the following formula in which G is an aryl or a heterocyclic ring, R11 and R12 are hydrogen or an alkyl, X is sulfur or oxygen, R2 and R3 are hydrogen, an substituent such as an alkyl and J is pyridyl or phenyl having substituents and a heterocyclic ring may be formed between R2, R3 and J is provided here and is useful in the pharmacological field. STR1
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- Polycyclic amines useful as cerebrovascular agents
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A novel series of polycyclic amines, derivatives, methods of making the compounds, novel intermediates, compositions containing them, and methods for using them in the treatment and prevention of cerebrovascular disorders are disclosed.
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- 2-substituted-e-fused-[1,2,4]triazolo[1,5-c]pyrimidines, pharmaceutical compositions, and uses thereof
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Compounds of the formula STR1 wherein R 1 is optionally substituted phenyl, pyridyl, thienyl, furyl, pyrrolyl, thiazolyl, or ribofuranosyl; X is oxygen, NR, or sulfur; R is hydrogen, lower alkyl, lower alkenyl, or lower alkynyl; and ring A is (a) an optionally substituted 5-8 membered monocycloalken-1,2-diyl; (b) an optionally substituted carbobicyclic ring of the formula STR2 wherein n and m are each independently one or two; or (c) an optionally substituted 5-6 membered heterocycle having one or two heteroatoms, the atoms of which are selected from carbon, oxygen, nitrogen, and sulfur. Also disclosed are tautomers of the above and pharmaceutically acceptable salts; compositions thereof; and methods of using the compounds, tautomer, or salts.
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- Agonists and antagonists to nicotine as smoking deterents
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Agonists and antagonists to nicotine are used as smoking deterrents.The nicotinic antagonists have the following structural requirements:(1) Aromatic, cycloalkyl, and heterocyclic carbamic acid esters of di- and trialkylaminoalkyl alcohols.(2) Aromatic, cycloalkyl, and heterocyclic thiocarbamic acid esters of di- and trialkylaminoalkyl alcohols.(3) Aromatic, cycloalkyl, and heterocyclic carboxylic acid esters of di- and trialkylaminoalkyl alcohols.(4) Aromatic, cycloalkyl, and heterocyclic carboxylic acid esters of heterocyclic amino alcohols.(5) Lobelia alkaloids: lobeline, lobelanine, and lobelanidine.The nicotinic agonists (nicotine-like) have the following structural requirements:(1) methylcarbamic acid esters of di- and trialkylaminoalkyl alcohols.(2) methylthiocarbamic acid esters of di- and trialkylaminoalkyl alcohols.
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- ALCOHOLYSIS OF 1,2-BIS(1-ISOCYANATO-1-METHYLETHYL)DIAZENE: UNEXPECTED FORMATION OF 5,5-DIMETHYL-1,2,4-TRIAZOLIN-2-ONE
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From the reaction of the bis(isocyanatoalkyl)diazene 1 with alcohols the expected adducts 2 could not be isolated (though there is spectroscopic evidence of their formation).The main product obtained was the triazolin-3-one 3, and in addition, several complementing products 4-6 were formed.
- Schantl, Joachim G.,Gstach, Hubert,Lanznaster, Norbert
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p. 1439 - 1444
(2007/10/02)
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- Synthese von cis-2,3-Diisopropyltriaziridin-1-carbonsaeureestern
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Irradiation of the (Z)-azimines 1a,b in Et2O with a Hg high pressure lamp through Corex yielded (besides 30percent of the previously described trans-triaziridines 3a,b) 15percent of the new cis-triaziridines 4a,b.The same irradiation of the (E)-azimines 2a,b afforded only 15-18percent of 3a,b but 20-23percent of 4a,b.Thus, these azimine photocyclizations show some stereospecificity.The triaziridines 3a,b and 4a,b formed in this way were always accompanied by the same three types of by-products, namely 10-15percent of the 'triazones' 5a,b, 11-20percent of the carbamic esters 6a,b, and 5-10percent of the ether/nitrene insertion products 7a,b.The constitution and configuration of the new cis-triaziridines 4 followed from their spectral properties.Of particular interest are the symmetry properties of 4 derived from the 1H-, 13C-, and 15N-NMR spectra: The stereoisomers 3 and 4 differ only in that the isochronicity of the two constitutionally equivalent molecular halves is temperature dependent in 3 but independent in 4.Both triaziridines 3 and 4 exhibit the IR CO band at (for carbamates) remarkably high frequency.The results confirm that the alkyl-substituted N-atoms of triaziridines are pyramidally stable, that the corresponding acyl-substituted N-atoms (N(1)) are also pyramidal, but can invert more readily, and that rotation around the N(1), C(=O) bond is rapid.Thus, there can be only little amide-type delocalization between a triaziridine N-atom and an acyl substituent of the carbamate type attached to it.
- Hilpert, Hans,Hoesch, Lienhard,Dreiding, Andre S.
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p. 1691 - 1697
(2007/10/02)
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- Fluorinated diaminobutane derivatives
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Fluorinated diaminobutane compounds in vivo are inhibitors of gamma-aminobutyric acid transaminase and have the following formula: STR1 wherein: R1 represents hydrogen, C1 -C6 alkyl, or phenyl-(C1 -C4 alkyl); R2 represents hydrogen, C1 -C6 alkyl, phenyl-(C1 -C4 alkyl), or R4, where R4 is as defined below; R3 represents hydrogen, or, except when R2 represents R4, R4, where R4 is as defined below; each R4, independently, represents C2 -C5 alkylcarbonyl, phenylcarbonyl, phenyl-(C1 -C4 alkyl) carbonyl, or an aminocarboxylic acid residue derived by removal of an hydroxy group from the carboxy moiety of an L-aminocarboxylic acid; and p represents 1 or 2, and pharmaceutically acceptable acid addition salts thereof.
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- Process for the production of delta 4-C21-steroid compounds
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C21-steroid compounds with a nitrogen function in the 20-position corresponding to general formula I below STR1 in which Y is hydrogen, a hydroxyl group or, together with the C-atom substituted by Y, represents a carbonyl group or may even be replaced by a 9(11)-ene bond and in which X is hydrogen, acyl, a carbonic acid ester residue or, together with the adjacent hydrogen atom on the nitrogen, represents a carbonyl group, may be obtained by converting the steroid-C20-carboxylic acid halides structurally analogous to the required reaction product into the corresponding carboxylic acid azide and either transforming the carboxylic acid azide thus formed into the C20-isocyanate through the elimination of nitrogen and, if desired, converting the C20-isocyanate thus obtained into the C20-carbamate and/or the C20-amine or directly transforming the carboxylic acid azide into the C20-amine. The compounds thus produced corresponding to general formula I, in which Y represents an oxygen function or in which the substituent Y is replaced by a 9(11)-ene bond, are new. The 20 amino compounds are readily converted to progesterone and other useful steroids.
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- REACTION OF ACTIVATED AZIRIDINES WITH AMINES
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The reactions of 1-alkoxycarbonylaziridines, 1-(phenylaminocarbonyl)aziridine, and 1-arylsulfonylaziridines with ammonia and amines were investigated.It was shown that the opening of the aziridine ring in a number of cases is accompanied by aminolysis of the alkoxycarbonyl group.The dependence of the ratio of ring opening and aminolysis products on the structure of the amines is discussed.
- Baranov, S. V.,Mochalin V. B.
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p. 951 - 953
(2007/10/02)
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