- Short time modification of carboxylated multi-wall nanotubes with amino uracil derivative
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In this study, the chemical functionalization of carboxylated multi-walled carbon nanotubes (MWNT-COOH) by Amino uracil derivative via microwave- assisted amidation method have been investigated.The functionalized MWNTs were characterized by Fourier Transform Infrared spectroscopy (FT-IR), Raman spectroscopy, elemental analysis and scanning electron microscopy (SEM). The major advantage of this procedure is reducing the reaction time to the order of minutes and the amidation was completed in one step as compared to two in the conventional approach. The acid chloride formation step was eliminated here.
- Zomorodbakhsh, Shahab,Mirza, Behrooz,Yazdizadeh, Shima,Tavahodi, Ehsan
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Read Online
- Prebiotic Origin of Pre-RNA Building Blocks in a Urea “Warm Little Pond” Scenario
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Urea appears to be a key intermediate of important prebiotic synthetic pathways. Concentrated pools of urea likely existed on the surface of the early Earth, as urea is synthesized in significant quantities from hydrogen cyanide or cyanamide (widely accepted prebiotic molecules), it has extremely high water solubility, and it can concentrate to form eutectics from aqueous solutions. We propose a model for the origin of a variety of canonical and non-canonical nucleobases, including some known to form supramolecular assemblies that contain Watson-Crick-like base pairs.The dual nucleophilic-electrophilic character of urea makes it an ideal precursor for the formation of nitrogenous heterocycles. We propose a model for the origin of a variety of canonical and noncanonical nucleobases, including some known to form supramolecular assemblies that contain Watson-Crick-like base pairs. These reactions involve urea condensation with other prebiotic molecules (e. g., malonic acid) that could be driven by environmental cycles (e. g., freezing/thawing, drying/wetting). The resulting heterocycle assemblies are compatible with the formation of nucleosides and, possibly, the chemical evolution of molecular precursors to RNA. We show that urea eutectics at moderate temperature represent a robust prebiotic source of nitrogenous heterocycles. The simplicity of these pathways, and their independence from specific or rare geological events, support the idea of urea being of fundamental importance to the prebiotic chemistry that gave rise to life on Earth.
- Menor Salván,Bouza, Marcos,Fialho, David M.,Burcar, Bradley T.,Fernández, Facundo M.,Hud, Nicholas V.
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p. 3504 - 3510
(2020/10/02)
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- Preparation method for 4-amino-2,6-dimethoxypyrimidine
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The invention discloses a preparation method for 4-amino-2,6-dimethoxy pyrimidine. According to the method, with cyanoacetate and urea as raw materials, the 4-amino-2,6-dimethoxypyrimidine is synthesized through a cyclization and methylation two-step method. The preparation method provided by the invention shortens production process steps, optimizes reaction conditions, improves the reaction yield, solves the problem that a large amount of colored phosphorus-containing wastewater is generated in the original process, and provides an effective way for efficient green industrial production of the 4-amino-2,6-dimethoxypyrimidine.
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Paragraph 0027-0030; 0041-0043
(2020/05/02)
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- Spectrophotometric investigation of 5-nitroso-6-aminouracil and its methyl derivative in methanol by selective complexation with bivalent metal ions
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6-Amino-5-nitrosouracils are synthesized by the condensation reaction of urea or N,N′-dimethyl urea, cyanoacetic acid and acetic anhydride followed by nitrosation reaction with sodium nitrite. The synthesized compounds are characterized by various spectroscopic techniques like FTIR, NMR, single crystal XRD, and UV–vis absorption spectroscopy. From a single-crystal X-ray crystallography study of DANU, it is found that the compound is crystalline with one water molecule. The binding properties of both compounds with various metal ions are studied using UV–vis spectroscopy, where ANU shows a colour change from colourless to yellow colour-forming complex with cobalt metal ion. While DANU shows a colour change from colourless to dark yellow forming complex with copper and nickel cation, respectively. These compounds showed the job's plots with Cu2+, Ni2+, and Co2+ in various stoichiometric ratios to form the respective metal complex. The association/binding constant (Ka) values are calculated by plotting Benesi–Hilderbrand plots of ANU with Co2+ ion and is found to be 9.524 × 102. Whereas, DANU with Cu2+, Ni2+ are found to be 3.956 × 103, 2.041 × 103, respectively. These cations may be used in metal ions complexation for the respective ligand. The LOD values for ANU-Co2+, DANU-Cu2+ & DANU-Ni2+ are obtained as 33.9428 μM, 93.8082 μM and 48.396 μM, respectively, whereas the LOQ values are found as 102.857 μM, 284.2675 μM and 146.653 μM, respectively.
- Das, Subrata,Hussain, Sahid,Kumar, Brajesh,Kumar, Pramanand,Sugunakara Rao, Mugada
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- Method for preparing 4-amino-2,6-dihydroxypyrimidine by virtue of dry frying process
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The invention belongs to the field of medicinal chemical synthesis and in particular relates to a method for preparing 4-amino-2,6-dihydroxypyrimidine by virtue of a dry frying process. The method forpreparing 4-amino-2,6-dihydroxypyrimidine by virtue of the dry frying process comprises the following concrete steps: by taking sodium methoxide dry powder, urea and methyl cyanoacetate as raw materials, reacting under certain conditions, heating at a certain temperature, steaming out generated methanol, and finally generating 4-amino-2,6-dihydroxypyrimidine. According to the invention, yield of4-aminopyrimidine obtained through cyclization reaction can reach 80-85%, and product purity is more than 99%. Compared with a liquid-phase cyclization method, the method provided by the invention hasthe advantages that reaction yield can be improved by more than 15%, reaction period is reduced to be 2-3 hours from the original more than 8 hours, and no water methanol is produced, so that pollution of organic wastewater is greatly reduced, preparation cost and energy consumption of 4-amino-2,6-dihydroxypyrimidine are greatly reduced, and the method provided by the invention is hopeful to being applied to industrial production.
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Paragraph 0021-0022; 0023-0024; 0025-0026
(2018/04/03)
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- Novel riboflavin-inspired conjugated bio-organic semiconductors
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Flavins are known to be extremely versatile, thus enabling routes to innumerable modifications in order to obtain desired properties. Thus, in the present paper, the group of bio-inspired conjugated materials based on the alloxazine core is synthetized using two efficient novel synthetic approaches providing relatively high reaction yields. The comprehensive characterization of the materials, in order to evaluate the properties and application potential, has shown that the modification of the initial alloxazine core with aromatic substituents allows fine tuning of the optical bandgap, position of electronic orbitals, absorption and emission properties. Interestingly, the compounds possess multichromophoric behavior, which is assumed to be the results of an intramolecular proton transfer.
- Richtar, Jan,Heinrichova, Patricie,Apaydin, Dogukan Hazar,Schmiedova, Veronika,Yumusak, Cigdem,Kovalenko, Alexander,Weiter, Martin,Sariciftci, Niyazi Serdar,Krajcovic, Jozef
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- A 4 - amino uracil synthesis and purification method
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The invention discloses a synthesizing and purifying method for 4-aminouracil. The method comprises the following steps of: (a) adding solid cyanoacetic acid, urea and acetic oxide into a reaction bottle for reacting for 1-5 hours at the temperature of 40-120 DEG C; (b) adding hydroxide into the step (a) for reacting for 1-3 hours; (c) neutralizing by using inorganic acid and adding acetone, and purifying a product by means of double solvent treatment. The method is simple in process and convenient to carry out; the obtained product is high in purity and high in yield.
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Paragraph 0014; 0015; 0016; 0017; 0018; 0019; 0020-0033
(2017/08/26)
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- Fused Heterocyclic Compounds as Potent Indoleamine-2,3-dioxygenase 1 Inhibitors
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Uncontrolled metabolism of l-tryptophan (l-Trp) in the immune system has been recognized as a critical cellular process in immune tolerance. Indoleamine 2,3-dioxygenase 1 (IDO1) enzyme plays an important role in the metabolism of a local l-Trp through the kynurenine pathway in the immune systems. In this regard, IDO1 has emerged as a therapeutic target for the treatment of diseases that are associated with immune suppression like chronic infections, cancer, and others. In this study, we synthesized a series of pyridopyrimidine, pyrazolopyranopyrimidine, and dipyrazolopyran derivatives. Further lead optimizations directed to the identification of potent compounds, 4j and 4l (IC50 = 260 and 151 nM, respectively). These compounds also exhibited IDO1 inhibitory activities in the low nanomolar range in MDA-MB-231 cells with very low cytotoxicity. Stronger selectivity for the IDO1 enzyme (>300-fold) over tryptophan 2,3-dioxygenase (TDO) enzyme was also observed for these compounds. Hence, these fused heterocyclic compounds are attractive candidates for the advanced study of IDO1-dependent cellular function and immunotherapeutic applications.
- Panda, Subhankar,Roy, Ashalata,Deka, Suman Jyoti,Trivedi, Vishal,Manna, Debasis
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supporting information
p. 1167 - 1172
(2016/12/16)
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- Synthesis and evaluation of antitumour activities of novel fused tri-And tetracyclic uracil derivatives
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Simple one-pot syntheses of indenopyrrolopyrimidines and indolopyrrolopyrimidines were achieved via the cyclocondensation of 6-Aminouracils and, respectively, ninhydrin and isatin in the presence of catalytic amounts of glacial acetic acid. Similarly, 5,6-diaminouracil derivatives were used as starting materials for the synthesis of indenopteridines and indolopteridines via their reaction with ninhydrin and isatin, respectively. The synthesised compounds were evaluated for antitumour activity against a human hepatocellular carcinoma cell line (HepG2), some showing antitumour activity comparable with 5-fluorouracil and imatinib.
- Elkalyoubi, Samar,Fayed, Eman
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p. 771 - 777
(2017/01/03)
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- 5-Deazaflavin derivatives as inhibitors of p53 ubiquitination by HDM2
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Based on previous reports of certain 5-deazaflavin derivatives being capable of activating the tumour suppressor p53 in cancer cells through inhibition of the p53-specific ubiquitin E3 ligase HDM2, we have conducted an structure-activity relationship (SAR) analysis through systematic modification of the 5-deazaflavin template. This analysis shows that HDM2-inhibitory activity depends on a combination of factors. The most active compounds (e.g., 15) contain a trifluoromethyl or chloro substituent at the deazaflavin C9 position and this activity depends to a large extent on the presence of at least one additional halogen or methyl substituent of the phenyl group at N10. Our SAR results, in combination with the HDM2 RING domain receptor recognition model we present, form the basis for the design of drug-like and potent activators of p53 for potential cancer therapy.
- Dickens, Michael P.,Roxburgh, Patricia,Hock, Andreas,Mezna, Mokdad,Kellam, Barrie,Vousden, Karen H.,Fischer, Peter M.
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p. 6868 - 6877
(2013/11/06)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Preparation, chemical and biological study of acyclovir analogue starting from 6-aminouracil
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6-aminouracil14, dibenzosulphonyl ethyl amine11 have been prepared, as starting materials to be introduced as an alkylating reagent with sodium carbonate as catalyst. Acyclovir analogue15 was prepared for the first time, the expected structure of the final newly acyclovir analogue was determined on the basis of NMR, IR, and mass spectroscopy, with low cost, high selectivity, safe and mild reaction conditions.
- Essa, Fadhil B.,Bazbouz, Akram,Al-Lababidi, Suzan
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experimental part
p. 1281 - 1292
(2011/10/31)
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- Approach to the library of fused pyridine-4-carboxylic acids by combes-type reaction of acyl pyruvates and electron-rich amino heterocycles
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A library of fused pyridine-4-carboxylic acids (including pyrazolo[3,4-b]pyridines, isoxazolo[5,4-b]pyridines, furo[2,3-b]pyridines, thieno[2,3-b]pyridines, and pyrido[2,3-d]pyrimidines) was generated by Combes-type reaction of acyl pyruvates and electron-rich amino heterocycles followed by hydrolysis of the ester. The library members were also demonstrated to undergo the standard combinatorial transformations including amide coupling and esterification, as well as less common heterocyclizations to 1,2,4-triazoles and 1,2,4-oxadiazoles.
- Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Plaskon, Andrey S.,Dmytriv, Yuri V.,Grygorenko, Oleksandr O.,Mykhailiuk, Pavel K.,Krotko, Dmitriy G.,Pushechnikov, Alexei,Tolmachev, Andrey A.
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scheme or table
p. 510 - 517
(2010/09/05)
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- Inactivation of nitric oxide by uric acid
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The 1980 identification of nitric oxide (NO) as an endothelial cell-derived relaxing factor resulted in an unprecedented biomedical research of NO and established NO as one of the most important cardiovascular, nervous and immune system regulatory molecule. A reduction in endothelial cell NO levels leading to endothelial dysfunction has been identified as a key pathogenic event preceding the development of hypertension, metabolic syndrome, and cardiovascular disease. The reduction in endothelial NO in cardiovascular disease has been attributed to the action of oxidants that either directly react with NO or uncouple its substrate enzyme. In this report, we demonstrate that uric acid (UA), the most abundant antioxidant in plasma, reacts directly with NO in a rapid irreversible reaction resulting in the formation of 6-aminouracil and depletion of NO. We further show that this reaction occurs preferentially with NO even in the presence of oxidants peroxynitrite and hydrogen peroxide and that the reaction is at least partially blocked by glutathione. This study shows a potential mechanism by which UA may deplete NO and cause endothelial dysfunction, particularly under conditions of oxidative stress in which UA is elevated and intracellular glutathione is depleted. Copyright Taylor & Francis Group, LLC.
- Gersch, Christine,Palii, Sergiu P.,Kim, Kyung Mee,Angerhofer, Alexander,Johnson, Richard J.,Henderson, George N.
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p. 967 - 978
(2008/12/22)
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- Microwave-expedited one-pot, two-component, solvent-free synthesis of functionalized pyrimidines
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The synthesis of a series of diversely substituted pyrimidines under solvent-free conditions in good yields is described. Under microwave irradiation, a variety of nucleophilic substrates containing the N?C?N unit with ?-dicarbonyl compounds, ethyl cyanoacetate, malononitrile, and chalcones was cyclized to give pyrimidines. A combinatorial type approach for a one-step synthesis has been developed where a ring-closing condensation is followed by spontaneous aromatization to afford 28 functionalized and aryl/alkyl substituted pyrimidines. CSIRO 2007.
- Goswami, Shyamaprosad,Jana, Subrata,Dey, Swapan,Kumar Adak, Avijit
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p. 120 - 123
(2008/02/11)
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- A facile synthesis of pyrrolo-[3,2-d]pyrimidines from 6-azidouracils and ylide phosphoranes
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A series of the title compounds, 9-deazaxanthines, was regioselectively prepared in reasonable yields as major products from the reactions of 6-azidouracils 1a,b with stabilized ester-2a,b or keto-2c ylide phosphoranes and a moderated phosphorus ylide 3, instead of the expected triazoles. Side products were also observed wherein pyrimido[5,4-g]pteridine-2,4,5,7-tetrone (15) and other fused ring systems or acyclic-substituted uracil derivatives were isolated. A comparative study on the reactivity of 1a in analogy to 1b toward phosphoranes is also described.
- Abdou, Wafaa M.,Fahmy, Amin F. M.,Kamel, Azza A.
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p. 357 - 365
(2007/10/03)
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- Synthesis of purine antiviral agents, hypoxanthine and 6-mercaptopurine
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Some potentially biologically active 6-substituted purine derivatives have been synthesized from simple organic reagents. The reaction of urea with ethyl cyanoacetate gave 6-aminopyrimidine-2,4-dione which was converted in two steps into purine derivative, xanthine. The latter was treated with formamide at 200°C to obtain hypoxanthine. The chlorination of hypoxanthine with POCl3 gave 6-chloropurine which was converted into 6-mercaptopurine via reaction with thiourea in acetonitrile, followed by treatment with boiling ethanol.
- Sariri,Khalili
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p. 1053 - 1055
(2007/10/03)
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- Reactions of nitriles under acidic conditions : Part IX - Synthesis of 6-amino-1-aryluracils, 6-amino-1-aryl-2-thiouracils and 6-amino-1,3-diaryl-2-thiouracils under acidic conditions
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6-Amino-1-aryluracils (11a-g), 6-amino-1-aryl-2-thiouracils (12a-g), and 6-amino-1,3-diaryl-2-thiouracils (6a,b) have been synthesised through the dry hydrogen chloride gas-catalysed condensation of ethyl cyanoacetate (7) with appropriate arylureas and thioureas. 1-Aryl (12a-g) and 1,3-diaryl-2-thiouracils (6c-g) have been converted to the corresponding 1-aryl (15a-g) and novel hitherto unre-ported, 1,3-diaryluracils (5a-e) through their oxidative desulphurisation.
- Shishoo,Jain,Jain,Shah,Ravikumar
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p. 662 - 668
(2007/10/03)
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- Synthesis, anticancer and antimicrobiological activities of pyrrolo[2,3-d]pyrimidines
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Reactions of 6-amino-3,4-dihydro-2-methoxy-4-oxopyrimidine 1a and its 3-methyl derivative 1b with chloroacetaldehyde and chloroacetyl chloride are discussed in this paper. Amongst others compounds, we have obtained, in low yield, the novel ring system oxazolo[3,2-c]pyrrolo[3,2-e]pyrimidine. The anticancer and anti-microbial activities of some of the obtained products are described.
- Quijano,Nogueras,Sanchez,Alvarez de Cienfuegos,Melgarejo
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p. 1079 - 1083
(2007/10/02)
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- Decarbonylation of Some Pyrimidine-5-carboxaldehydes
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In the course of determining the ultraviolet spectra of some 2,4,6-trisubstituted-pyrimidine-5-carboxaldehydes we discovered the facile loss of the formyl group.The reaction appears to be restricted to pyrimidine-5-carboxaldehydes containing three strongly electron donating substituents.Loss of the formyl group occurs at room temperature only in methanol with large excess of acid.Other alcohols and water fail to afford the decarbonylated product.A suggested pathway for this reaction is offered.
- Delia, Thomas J.,Polenz, Barry,Martin, Mary C.
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p. 1697 - 1700
(2007/10/02)
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