- The efficient one-step chlorination of methylsulfanyl group on pyrimidine ring system with sulfuryl chloride
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A facile one-step transformation of methylsulfanyl and arylsulfanyl groups on pyrimidine ring system into the corresponding chloride group was achieved using sulfuryl chloride in acetonitrile/dichloromethane.
- Ham, Young Jin,Lee, Duck-Hyung,Choi, Hwan Geun,Hah, Jung-Mi,Sim, Taebo
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Read Online
- 4,6-dichloropyrimidine preparation method
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The invention discloses a 4,6-dichloropyrimidine preparation method, which comprises: carrying out a cyclization reaction on a compound represented by a formula I and malononitrile in a sodium alcoholate system, evaporating to remove the alcohol after the cyclization reaction, adding water to dissolve, regulating the pH value with an acid, and carrying out cooling crystallization to obtain a compound represented by a formula II, wherein in the compound represented by a formula I, X is HCl, HNO3, H2SO4 or acetic acid; and adding hydrochloric acid and sodium nitrite into the compound representedby the formula II, carrying out a diazotization reaction, carrying out a Sandmeyer reaction under catalysis, extracting with a polar solvent after the reaction, and distilling to obtain a compound represented by a formula III, ie., 4,6-dichloropyrimidine.
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Paragraph 0044; 0046; 0047; 0048; 0050; 0051; 0052; 0054
(2020/02/14)
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- Preparation method of 4, 6-dichloropyrimidine
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The invention discloses a preparation method of 4, 6-dichloropyrimidine, which comprises the following steps: (1) dissolving 4, 6-dihydroxypyrimidine and a catalyst in a polar solvent, and mixing to obtain a mixed solution containing 4, 6-dihydroxypyrimidine; (2) adding chlorine or liquid chlorine into the mixed solution, and reacting to obtain a mixed solution containing 4, 6-dichloropyrimidine;(3) distilling the mixed solution containing 4, 6-dichloropyrimidine to remove the solvent, deacidifying, and distilling to recover byproduct phosphorus oxychloride, thereby obtaining a 4, 6-dichloropyrimidine crude product; (5) carrying out extraction separation on the 4, 6-dichloropyrimidine crude product, carrying out flash evaporation to remove a solvent and leave 4, 6-dichloropyrimidine in awater phase; and cooling and crystallizing the water phase, and carrying out dehydration treatment to obtain the 4, 6-dichloropyrimidine product. According to the method, the low-price easily-available catalyst is adopted, so that the reaction efficiency can be remarkably improved; chlorine/liquid chlorine is used as a chlorinating agent, so that the risk of the process is greatly reduced, and thebyproduct phosphorus oxychloride with high additional value is produced.
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Paragraph 0016; 0030-0045
(2020/08/27)
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- Efficient Phosphorus-Free Chlorination of Hydroxy Aza-Arenes and Their Application in One-Pot Pharmaceutical Synthesis
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The chlorination of hydroxy aza-arenes with bis(trichloromethyl) carbonate (BTC) and SOCl2 has been effectively performed by refluxing with 5 wt % 4-dimethylaminopyridine (DMAP) as a catalyst. Various substrates are chlorinated with high yields. The obtained chlorinated aza-arenes can be used directly with simple workup for succedent one-pot synthesis on a large scale.
- Wang, Jian,Li, Yan-Hui,Pan, Song-Cheng,Li, Ming-Fang,Du, Wenting,Yin, Hong,Li, Jing-Hua
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supporting information
p. 146 - 153
(2020/03/10)
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- Synthesis process 4,6-dichloropyrimidine (by machine translation)
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The invention provides a method 4,6 - for synthesizing,dichloropyrimidine as the raw material, with,hydroxypyrimidine as the reaction, 4,6 -dimethylaniline is used as the reaction, and the part of wastewater generated by,dimethylaniline in the finally produced wastewater N,N - according to the present invention is not limited to the consumption amount of the.dichloropyrimidine product produced by the invention, as a raw material. 4,6 - The present invention provides a method for producing waste water, by rectification in a manner of rectifying the product by distillation in a manner of rectifying, the product by a rectification method according to the present invention as a raw material solution, and a, solvent; in 1kg4,6 - a solvent; according to the present invention as a raw material of the present 6 - 7kg, invention in the present invention. (by machine translation)
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Paragraph 0015-0017; 0019; 0020
(2020/04/22)
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- Design, synthesis, and anticancer evaluation of acetamide and hydrazine analogues of pyrimidine
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A library of acetamide and hydrazine analogues were generated on the pyrimidine ring through a multistep reaction starting from 5-nitro-pyrimidine-4,6-diol and pyrimidine-4,6-diol, respectively. The synthesized analogues were screened for in vitro cytotoxic activity against various human cancer cell lines like HCT-1 and HT-15 (colon), MCF-7(breast), PC-3 (prostrate), SF268 (CNS) using MTT method. From the bioassay results, it was observed that even though many of the synthesized derivatives exhibited a good potency against various screened cancer cell lines, compound 14a from the acetamide series was found to show potent anticancer activity on all the tested cancer cell lines with IC50 value of 0.36μM on CNS cell line and 1.6μM on HT-21 cell line, and compound 19xxi from hydrazine series of pyrimidine showed potent activity against three tested cancer cell lines with IC50 value of 0.76μM on HT-29 cell line, 2.6μM on HCT-15, and 3.2μM on MCF-7 cell line.
- Chashoo, Gousia,Khazir, Jabeena,Maqbool, Tariq,Mir, Bilal Ahmad,Pilcher, Lynne,Riley, Darren
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- Pyrimidine hydrazone derivative and preparation method and application thereof
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The invention relates to pyrimidine hydrazone derivatives as shown in a chemical structural formula I or II, pharmaceutically acceptable salts and pharmaceutical compositions thereof, and an application of the pyrimidine hydrazone derivatives and the pharmaceutically acceptable salts and the pharmaceutical compositions in preparation of influenza virus neuraminidase inhibitors, wherein X is selected from: fluorine, chlorine, bromine, hydroxyl, dihydroxy, 2-hydroxy-3-methoxy, 2-hydroxy-4-methoxy, 2-hydroxy-5-C1-C2 alkoxy, 2-hydroxy-6-C1-C2 alkoxy, 3-hydroxy-2-C1-C2 alkoxy, 3-hydroxy-4-C1-C2 alkoxy, 3-hydroxy-5-methyl C1-C2 alkoxy , 3-hydroxy-6-C1-C2 alkoxy, 4-hydroxy-2-C1-C2 alkoxy, 4-hydroxy-3-C1-C2 alkoxy, 4-hydroxy-3, 5-diC1-C2 alkoxy, trihydroxy or 4-hydroxy-3,5-dimethyl; and Y is selected from: fluorine, chlorine, bromine, acetamido, hydroxyl or methoxy.
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Paragraph 0036-0037; 0041-0043
(2020/11/23)
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- Preparation method and application of 4, 6-dichloropyrimidine
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The invention discloses a preparation method and application of 4, 6-dichloropyrimidine, and belongs to the technical field of chemical engineering. The structural formula of the 4, 6-dichloropyrimidine is C4H2Cl2N2, the molecular weight of the 4, 6-dichloropyrimidine is 148.98, and the 4, 6-dichloropyrimidine is light yellow to white crystals. The preparation method of the 4, 6-dichloropyrimidinecomprises the following steps of: mixing an organic phosphorus compound, phosphorus pentachloride and 4, 6-dihydroxypyrimidine in an organic solvent, controlling the temperature to be 120DEG C, and carrying out reaction for a certain time to obtain a mixed solution containing 4, 6-dichloropyrimidine and phosphorus oxychloride; cooling the mixed solution containing 4, 6-dichloropyrimidine and phosphorus oxychloride to room temperature, and performing extracting to obtain an organic phase; washing and concentrating the organic phase, and then conducting cooling and crystallizing to obtain pure4, 6-dichloropyrimidine. The method provided by the invention is easy to control in operation and good in safety, and after extraction, the catalyst and the phosphorus-containing by-product are not damaged and can be recycled, so that possibility is provided for comprehensive utilization of the phosphorus-containing by-product, and environmental pollution is avoided.
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Paragraph 0018-0021
(2020/10/30)
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- Preparation method of chloro-substituted polyhydroxy aza-aromatic ring compound (by machine translation)
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The invention discloses a preparation method, namely BTC and SOCl, of a chloropolyhydroxyl aza heteroaromatic ring compound as a raw material with a polyhydroxy aza heteroaromatic ring compound as a raw material, and a preparation method thereof. 2 As the double chlorination reagent, a chloropolyhydroxyl aza-aromatic ring compound is produced by chlorination reaction with 4 - dimethylaminopyridine (DMAP) as a catalyst at room temperature to reflux temperature of the reaction, as a catalyst. BTC TC TC TC2 /DMDMAP chlorination system has high efficiency, high selectivity and chlorine substitution on a polyhydroxy nitrogen heterocyclic compound; the system can replace POCl3 , The production of phosphorus-containing wastewater is avoided. Using BTC as a chlorination reagent, the reaction by-product was HCl and CO. 2 . From the aspects of industrial wastewater treatment, environmental protection and the like, the advantages thereof are obvious; SOCl is distilled off after the reaction is ended. 2 The quantity is almost no loss, can be used repeatedly, and reduces the process cost. (by machine translation)
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Paragraph 0019; 0020; 0021-0024
(2019/10/01)
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- In the stripping column in the application of the dichloro pyrimidine purification (by machine translation)
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The present invention provides a pure aliphatic chloro pyrimidine of stripping method, comprises the following steps: A) dihydroxy pyrimidine carried out after the chlorination reaction, to obtain dichloro pyrimidine reaction mixed solution; B) reaction mixed solution adding water hydrolysis, or by adding ice water to ice solution, then the organic solvent extraction, including two chlorine pyrimidine crude product obtained organic phase; C) containing dichloro pyrimidine crude organic phase is the top or upper part enters the stripping column, or the lower part of the water vapor from the bottom of the stripping column, containing two chloro pyrimidine crude organic phase flushes steams, including two chlorine pyrimidine pure product obtained organic phase; D) organic phase containing dichloro pyrimidine pure product, reduced pressure or normal pressure distillation concentrated, the temperature crystallization, centrifugation or filtration to obtain two chloro pyrimidine pure product. This invention adopts the reverse steam stripping column, two chloro pyrimidine crude to drip or spray mode, the state of the droplet, direct contact with water vapor, so that the purification efficiency, refining yield is greatly improved, and is suitable for industrial production and application. (by machine translation)
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Paragraph 0039-0041; 0044
(2018/09/08)
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- Synthetic method for 4,6-dichloropyrimidine
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The invention discloses a synthetic method for 4,6-dichloropyrimidine. The synthetic method comprises the following steps: (1) mixing 4,6-dihydroxypyrimidine with a catalyst, adding one or two selected from a group consisting of diphosgene and triphosgene, and carrying out a reaction; and (2) after the reaction is completed, separating and purifying a reaction solution so as to obtain the product4,6-dichloropyrimidine. The catalyst is a compound of organic phosphine and cobalt phthalocyanine. The synthetic method of the invention does not use any organic alkali, avoids the cumbersome processof recovery and recycling of the organic alkali, prevents the waste of resources and product loss, and is friendly to environment and free of additional solid waste and considerable phosphorus-containing waste liquid and waste residues; and a specific catalyst combination is used in the invention, the usage amount of the catalyst is small, and cost is low.
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Paragraph 0027; 0028; 0029; 0031-0033; 0039; 0040
(2018/09/08)
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- A 4, 6 - dichloro pyrimidine production process
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The present invention provides a 4, 6 - dichloro pyrimidine production process, comprises the following steps: 1) the 4, 6 - dihydroxy pyrimidine with phosphorus oxychloride mixing, and adding phosgene, diphosgene, triphosgene in one or several of the combined reaction; 2) in step 1) the resulting reaction solution prepared for separation and purification of phosphorus oxychloride and 4, 6 - two chlorine pyrimidine, recovery of phosphorus oxychloride as step 1) raw materials used for 4, 6 - dichloro pyrimidine synthesis reaction. The invention avoids the organic alkali recovery and reuse of the tedious process, also without the use of expensive catalyst, avoiding the wasting of resources and product loss, environmental friendly, will not produce the additional of solid waste, also will not produce a large amount of phosphorus-containing liquid and waste residue, and high product yield, purity is good, without secondary purification can reach commercial requirements, can be used for large-scale industrial production.
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Paragraph 0027; 0028; 0030; 0032; 0034; 0036; 0038; 0040
(2018/07/07)
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- Method for preparing 4,6-dichloropyrimidine under sulfuric acid catalysis
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The invention relates to a method for preparing 4,6-dichloropyrimidine under sulfuric acid catalysis. By the adoption of the method, the problems that the yield of 4,6-dichloropyrimidine is low, cost is high, and industrial production is hard to achieve can be effectively solved. According to the method, in the presence of sulfuric acid, triphosgene or diphosgene reacts with 4,6-dihydroxypyrimidine; specifically, 4,6-dihydroxypyrimidine, sulfuric acid and N,N-dimethyl formamide are mixed evenly and heated to 80-100 DEG C to form a mixed solution, triphosgene or diphosgene is dissolved in a solvent and added into the mixed solution within 1-2 h dropwise slowly, heat insulation and stirring are continued for 3 h, temperature is reduced to room temperature, then the product is poured into ice water, and an organic solvent layer is separated out, washed, and dried with anhydrous magnesium sulfate to generate the 4,6-dichloropyrimidine. The method is simple, operation is easy, raw materials are rich, cost is low, product quality is high, the yield is high, organic matter is easy to recycle, environment pollution is avoided, industrial production is facilitated, and economic and social benefits are great.
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Paragraph 0011
(2016/11/14)
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- Synthetic method of 4,6-dichloropyrimidine
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The invention provides a synthetic method of 4,6-dichloropyrimidine, comprising the following steps: 1), mixing 4,6-dihydroxypyrimidine with phosphorus oxychloride, and adding one of, or a combination of any of, phosgene, diphosgene and triphosgene for the purpose of reacting; 2), separating and purifying a reaction liquid obtained in step 1) to obtain phosphorus oxychloride and 4,6-dichloropyrimidine, and subjecting the recycled phosphorus oxychloride as material of step 1) to 4,6-dichloropyrimidine synthetic reaction.The complex process of organic base recycling and reutilization is avoided, no expensive catalyst is used, resource waste and product loss are avoided, the method is environment-friendly, no extra solid waste is produced, no mass phosphorus-containing waste liquid and residue are produced, product yield is high, product purity is good, a product may be commercially available without secondary purification, and the method is useful in large-scale industrial production.
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Paragraph 0027; 0028
(2016/12/01)
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- Synthesis of 4,6-dichloropyrimidine and process optimization
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The invention provides synthesis of 4,6-dichloropyrimidine and process optimization. The synthesis comprises the following main steps: (1) mixing dimethyl malonate and formamide, dripping the mixed solution into a sodium methylate-methanol solution, stirring, after the reaction is completed, distilling out methanol, recycling the methanol, further adding water to dissolve solid, continuously dripping diluted hydrochloric acid to adjust the pH value of the solution to be 2-3, leaving to stand, performing suction filtration, washing, and drying so as to obtain a product, that is, 4,6-dichloropyrimidine; (2) adding 4,6-dichloropyrimidine, trichloromethane and pyridine into a reaction kettle, stirring, slowly introducing phosgene, controlling the reaction temperature, after the reaction is completed, performing reduced pressure distillation to remove an excessive solvent trichloromethane so as to obtain a 4,6-dichloropyrimidine solution, performing suction filtration, concentrating, and crystallizing to obtain a white needle-shaped product, that is, 4,6-dichloropyrimidine. Compared with the prior art, the preparation method provided by the invention is simple, free of phosphorus-containing byproduct, and high in product yield and purity.
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Paragraph 0023; 0024
(2016/12/01)
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- Synthetic process for preparing 4,6-dichloropyrimidine through one-step method
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The invention discloses a synthetic process for preparing 4,6-dichloropyrimidine through a one-step method. The synthetic process comprises the following steps: (1) phosgenation reaction; (2) waste gas treatment, trichloromethane and pyridine material recycle, and 4,6-dichloropyrimidine product refining. According to the synthetic process, through the arrangement of a phosgene distributor in a reactor, the effective utilization ratio of phosgene can be greatly improved, and the unit consumption of phosgene is reduced from 1.8 percentage points to 1.2 percentage points; through the arrangement of an alkali liquor spraying system above a gathering tank, hydrogen chloride and phosgene can be effectively absorbed, and leakage of toxic gases can be avoided; meanwhile, through the arrangement of a draught fan, mixed gas can upwards enter the spraying system to be absorbed; through the setting of different rectification temperatures to recycle the materials, the cost is reduced, and the recycle of resources can be realized.
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Paragraph 0018; 0019
(2017/01/17)
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- Improved 4,6-dichloropyrimidine production process
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An improved 4,6-dichloropyrimidine production process includes steps: (1) phosgenation reaction; (2) rectification, to be more specific, collecting a trichloromethane fraction, cooling to the room temperature, and filling to store for recycling; (3) pyridine collection for recycling; (4) 4,6-dichloropyrimidine collection. By adoption of phosgene for substitution of phosphorus oxychloride in a traditional process, phosphorus containing by-products are avoided, so that environment protection is realized; by addition of a pyridine catalyst, reaction can be accelerated; pyridine is collected by means of solution pH adjustment, methyl tertiary butyl ether extraction, copper sulfate washing and the like, and accordingly pyridine leakage caused by traditional methods of rectification, rotary evaporation and the like is avoided, and personal safety of operators is guaranteed.
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Paragraph 0014; 0015; 0016
(2017/01/19)
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- Production process of 4,6-dichloropyrimidine
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The invention provides a production process of 4,6-dichloropyrimidine. The production process comprises the following steps: (1) adding 4,6-dihydroxypyrimidine, phosphorus oxychloride and toluene into a reaction kettle; starting a stirrer and stirring; dropwise adding DMF (Dimethyl Formamide) while stirring; (2) raising the temperature to 120 DEG C and reacting for 2 hours; carrying out refluxing reaction for 3 hours until a solution is layered; taking an upper-layer solution and transferring the upper-layer solution into a distillation tower; distilling at normal pressure to obtain the toluene and the DMF; (3) after filtering a residual product in the step (2), transferring the product into a crystallization kettle; carrying out recrystallization to obtain the 4,6-dichloropyrimidine; adjusting the pH (Potential of Hydrogen) of a crystallized mother solution by a hydroxide solution with the concentration of 10 percent and reducing the temperature of the solution; after separating out crystals, centrifuging and separating and then collecting a hydrated sodium hydrogen phosphate solid. By directly adding the toluene into the reaction raw materials and refluxing, the materials can generate a layering phenomenon, so that the extraction of a primary product is realized and experiment steps are simplified.
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Paragraph 0016; 0017
(2017/04/29)
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- Electron-deficient heteroarenium salts: An organocatalytic tool for activation of hydrogen peroxide in oxidations
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A series of monosubstituted pyrimidinium and pyrazinium triflates and 3,5-disubstituted pyridinium triflates were prepared and tested as simple catalysts of oxidations with hydrogen peroxide, using sulfoxidation as a model reaction. Their catalytic efficiency strongly depends on the type of substituent and is remarkable for derivatives with an electron-withdrawing group, showing reactivity comparable to that of flavinium salts which are the prominent organocatalysts for oxygenations. Because of their high stability and good accessibility, 4-(trifluoromethyl)pyrimidinium and 3,5-dinitropyridinium triflates are the catalysts of choice and were shown to catalyze oxidation of aliphatic and aromatic sulfides to sulfoxides, giving quantitative conversions, high preparative yields and excellent chemoselectivity. The high efficiency of electron-poor heteroarenium salts is rationalized by their ability to readily form adducts with nucleophiles, as documented by low pKR+ values (pKR+ red > -0.5 V). Hydrogen peroxide adducts formed in situ during catalytic oxidation act as substrate oxidizing agents. The Gibbs free energies of oxygen transfer from these heterocyclic hydroperoxides to thioanisole, obtained by calculations at the B3LYP/6-311++g(d,p) level, showed that they are much stronger oxidizing agents than alkyl hydroperoxides and in some cases are almost comparable to derivatives of flavin hydroperoxide acting as oxidizing agents in monooxygenases.
- ?turala, Ji?í,Bohá?ová, Soňa,Chudoba, Josef,Metelková, Radka,Cibulka, Radek
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p. 2676 - 2699
(2015/03/18)
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- IBD-mediated oxidative cyclization of pyrimidinylhydrazones and concurrent Dimroth rearrangement: Synthesis of [1,2,4]triazolo[1,5-c]pyrimidine derivatives
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Oxidative cyclization of 6-chloro-4-pyrimidinylhydrazones 4 with iodobenzene diacetate (IBD) in dichloromethane gives rise to [1,2,4]triazolo[4,3-c]pyrimidine derivatives 5a-o. These incipient products undergo feasible Dimroth rearrangement to furnish the isolated [1,2,4]triazolo[1,5-c]pyrimidines 6a-o in moderate to high yields.
- Tang, Caifei,Li, Zhiming,Wang, Quanrui
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p. 2629 - 2634
(2014/01/06)
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- A convenient route for the synthesis of novel 2-substituted [1,2,4]triazolo[1,5- C ]pyrimidine derivatives
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Reactions of easily accessible chloropyrimidinyl hydrazones with bromine were investigated. Oxidative cyclization followed by concomitant bromination led to the formation of [1,2,4]triazolo[4,3-c]pyrimidines, which then underwent the Dimroth rearrangement to afford highly functionalized 2-substituted [1,2,4]triazolo[1,5-c]pyrimidines.
- Li, Chao,Li, Zhiming,Wang, Quanrui
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scheme or table
p. 2179 - 2183
(2010/11/02)
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- Synthesis of chlorinated pyrimidines
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The invention provides a process for synthesizing chlorinated pyrimidines. The process includes reacting imidoyl chloride compounds with phosgene (COCl2). The imidoyl chloride compounds can be supplied as starting materials or can be produced by reacting organic amides with phosgene or reacting organic nitrites with hydrogen chloride. Phosgene may be replaced by equivalent reagents. The chlorinated pyrimidines, such as 4,6-dichloropyrimidine, can be used to synthesize other compounds useful in a variety of compositions, such as fungicides, pesticides, and pharmaceuticals.
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- Method for producing 4,6-dichloropyrimidine with sulfur compounds and phosphorus compounds
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The invention relates to a method for the preparation of 4,6-dichloropyrimidine by reacting 4-chloro-6-methoxypyrimidine with at least one sulphur-containing chlorinating agent selected from the group consisting of SCl2, SOCl2, and SO2Cl2in the presence of at least one phosphorus compound having the formula R3P═Yn??(1), in which R represents C1-C10-alkyl or C6-C10-aryl, each of which may optionally be substituted by up to five identical or different substituents selected from the group consisting of fluorine, chlorine, bromine, C1-C4-alkyl, and C1-C4-alkoxy, Y represents oxygen or sulphur, and n represents zero or 1.
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- Synthesis of chlorinated pyrimidines
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A facile process for the preparation of 4,6-dichloropyrimidine is provided, which utilizes quaternary ammonium salts or quaternary phosphonium salts as catalysts for the reaction of, for example, 4,6-dihydroxypyrimidine or 4-chloro-6-methoxypyrimidine with phosgene.
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- Method of producing 4,6-dichloropyrimidine with acid chlorides
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The present invention relates to a process for preparing 4,6-dichloro-pyrimidine by reaction of 4-chloro-6-methoxypyrimidine with an acid chloride in the presence of a hydrogen halide.
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- Synthesis of chlorinated pyrimidines
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The invention provides a process for synthesizing chlorinated pyrimidines. The process includes reacting imidoyl chloride compounds with phosgene (COCl2). The imidoyl chloride compounds can be supplied as starting materials or can be produced by reacting organic amides with phosgene or reacting organic nitrites with hydrogen chloride. The chlorinated pyrimidines, such as 4,6-dichloropyrimidine, can be used to synthesize other compounds useful in a variety of compositions, such as fungicides, pesticides, and pharmaceuticals.
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- Chemical process
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4,6-Dichloropyrimidine is prepared by treating 4,6-dihydroxypyrimidine with a chlorinating agent of the formula R1R2R3PCl2 wherein R1, R2 and R3 are independently alkyl or aryl, or one or more of the groups R1, R2 and R3 is linked to a polymer support. Conveniently, the chlorinating agent may be prepared in situ by reacting the corresponding phosphine oxide with phosgene. Thus, in a preferred process, 4,6-dichloropyrimidine is prepared by treating 4,6-dihydroxypyrimidine with phosgene in the presence of a phosphine oxide.
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- Process for the preparation of 4,6-dichloropyrimidine
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A process for preparing 4,6-dichloropyrimidine comprising treating 4,6-dihydroxy-pyrimidine with phosgene in the presence of a suitable base and optionally in the presence of a solvent.
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- Process for the preparation of polychloropyrimidines
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Polychloropyrimidines, in particular 4,6-dichloropyrimidine and 2,4,6-trichloropyrimidine, are obtained in a particularly advantageous manner from polyhydroxypyrimidines or tautomeric keto compounds thereof and excess phosphorus oxychloride in the presence of a tertiary amine if, in this reaction, a) 0.75 to 1.5 mol of phosphorus trichloride and 0.7 to 1.4 mol of chlorine per equivalent of hydroxyl groups to be replaced by chlorine are added such that an excess of phosphorus trichloride over chlorine is always present and b) phosphorus oxychloride and the polychloropyrimidine prepared are distilled off successively over a column under reduced pressure, or steps a) and b) are carried out in the reverse sequence, phosphorus trichloride also being distilled off before the phosphorus oxychloride in the case of b) after a) and phosphorus oxychloride which has formed again after step a) has been carried out being distilled off in the case of a) after b), and c) a strong base is added to the distillation residue which is then present, and the tertiary amine employed is recovered from this mixture by d) separating off the upper phase and e) purifying it by distillation, or carrying out steps d) and e) in the reverse sequence.
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- Process for the preparation of 4,6-dichloropyrimidines
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4,6-Dichloropyrimidines are obtained by the reaction of 4,6-dihydroxypyrimidines with excess phosphoryl chloride in a particularly advantageous manner when no base is added, during and/or after the reaction 0.75 to 1.5 mol of phosphorus trichloride and 0.7 to 1.3 mol of chlorine are added per equivalent of exchanged hydroxyl groups so that an excess of phosphorus trichloride with respect to chlorine is always present, and finally phosphorus trichloride and phosphoryl chloride are separated off. This process can be carried out in a particularly simple manner and also continuously.
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- Process for the preparation of chloropyrimidines
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A process for the preparation of chloropyrimidines of the formula STR1 in which the substituents may be alkyl, cycloalkyl, aryl or radicals containing heteroatoms, but in which at least one of the substituents R1 to R4 must be Cl, which involves: reacting a hydroxy-pyrimidine or its tautomeric keto form with phosphoryl chloride in the presence of an amine or amine hydrochloride; recovering phosphoryl chloride after the reaction by adding phosphorus pentachloride and distilling the phosphoryl chloride; and separating the chloropyrimidine from the amine hydrochloride by addition of a solvent which will dissolve the chloropyrimidine but not the amine hydrochloride and removing the amine hydrochloride.
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- An N.M.R. Study of Electron Donor-Electron Acceptor Interaction Between Aromatic Hydrocarbons and Diazines
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Equilibrium constants have been measured by n.m.r. spectroscopy for the electron donor-electron acceptor interaction between a number of aromatic hydrocarbons and diazines.The values obtained have shown that the interaction is weak, and that the aromatic hydrocarbon acts as the electron donor and the diazine as the electron acceptor in the systems studied.Chemical-shift data have provided evidence for the relative positioning of the donor and acceptor components within the various complexes.The effect of temperature on the equilibrium constant for complex formation between (2H6)benzene and pyrazine has shown that the enthalpy of format ion is close to zero.
- Hurst, Derek T.,Thakrar, Usha B.,Wells, Clifford H. J.,Wyer, John
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p. 1313 - 1319
(2007/10/02)
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