- Allyl amines as ammonia equivalents in the preparation of anilines and heteroarylamines
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A series of anilines and heteroarylamines were synthesized in moderate to excellent yields by palladium catalyzed cross coupling reaction of aryl or heteroaryl halides with allyl- or N,N-diallylamine followed by deallylation.
- Jaime-Figueroa, Saul,Liu, Yanzhou,Muchowski, Joseph M.,Putman, David G.
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- Degradation of sulfadiazine antibiotics by water falling film dielectric barrier discharge
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A new water falling film dielectric barrier discharge was applied to the degradation of sulfadiazine in the aqueous solution. The various parameters that affect the degradation of sulfadiazine and the proposed evolutionary process were investigated. The results indicated that the inner concentrations of 10 mg/L sulfadiazine can be all removed within 30 min. The optimum pH value was 9.10 and both strong acidic and alkaline solution conditions were not suitable for the degradation. The degradation of sulfadiazine can be enhanced by the addition of hydrogen radical scavengers, but be inhibited by adding hydroxyl radical scavengers. The water falling film dielectric barrier discharge was rather ineffective in mineralization, because of the intermediates were recalcitrant to be degraded. The existence of Fe2+ and CCl 4 in the liquid phase can promote the degradation and mineralization of sulfadiazine. It was found that the degradation of SDZ was enhanced by CCl4 was mainly because of the increase of OH due to the reaction of CCl4 with H that reduce the chances of their recombination with OH. Based on the 8 intermediate products identified by LC-MS, the proposed evolution of the degradation process was investigated.
- Rong, Shao-Peng,Sun, Ya-Bing,Zhao, Ze-Hua
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- Kinetic and mechanistic investigations on the oxidation of N'-heteroaryl unsymmetrical formamidines by permanganate in aqueous alkaline medium
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Kinetic studies on the oxidation of two substituted azinyl formamidines (Azn-Fs), namely N,N-dimethyl-N'-(pyrimidin-2-yl) formamidine (Pym-F) and N,N-dimethyl-N'-(pyridin-2-yl) formamidine (Py-F), by alkaline permanganate have been performed by spectrophotometry. The spectroscopic and kinetic evidence reveals the formation of 1:1 intermediate complexes between the oxidant and substrates. The influence of pH on the oxidation rates indicated that the reactions are base-catalyzed. The reactions show identical kinetics, being first order each in [MnO4 -]0 and [Azn-F] 0, but with a fractional first-order dependence on [OH-]. The effect of temperature on the reaction rate has been studied. Increasing ionic strength has no significant effect on the rate. The final oxidation products of Pym-F and Py-F were identified as 2-aminopyrimidine and 2-aminopyridine, respectively, in addition to dimethyl amine and carbon dioxide. Under comparable experimental conditions, the oxidation rate of Py-F is higher than that of Pym-F. A reaction mechanism adequately describing the observed kinetic behavior is proposed, and the reaction constants involved in the different steps of the mechanism have been evaluated. The activation parameters with respect to the rate-limiting step of the reactions, along with thermodynamic quantities, are presented and discussed.
- Fawzy, Ahmed,Shaaban, Mohamed R.
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- Efficient synthesis of aminopyridine derivatives by copper catalyzed amination reactions
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A copper(i) catalyzed amination reaction utilizing aqueous ammonia and operating under mild conditions is presented. This method was employed for the efficient synthesis of various aminopyridine derivatives bearing electron withdrawing and electron donating groups. The Royal Society of Chemistry 2010.
- Elmkaddem, Mohammed K.,Fischmeister, Cedric,Thomas, Christophe M.,Renaud, Jean-Luc
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- C2-Selective, Functional-Group-Divergent Amination of Pyrimidines by Enthalpy-Controlled Nucleophilic Functionalization
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Synthesis of heteroaryl amines has been an important topic in organic chemistry because of their importance in small-molecule discovery. In particular, 2-Aminopyrimidines represent a highly privileged structural motif that is prevalent in bioactive molecules, but a general strategy to introduce the pyrimidine C2-N bonds via direct functionalization is elusive. Here we describe a synthetic platform for site-selective C-H functionalization that affords pyrimidinyl iminium salt intermediates, which then can be transformed into various amine products in situ. Mechanism-based reagent design allowed for the C2-selective amination of pyrimidines, opening the new scope of site-selective heteroaryl C-H functionalization. Our method is compatible with a broad range of pyrimidines with sensitive functional groups and can access complex aminopyrimidines with high selectivity.
- Ham, Won Seok,Choi, Hoonchul,Zhang, Jianbo,Kim, Dongwook,Chang, Sukbok
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supporting information
p. 2885 - 2892
(2022/02/23)
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- Ordered mesoporous carbon as an efficient heterogeneous catalyst to activate peroxydisulfate for degradation of sulfadiazine
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Catalytic potential of carbon nanomaterials in peroxydisulfate (PDS) advanced oxidation systems for degradation of antibiotics remains poorly understood. This study revealed ordered mesoporous carbon (type CMK) acted as a superior catalyst for heterogeneous degradation of sulfadiazine (SDZ) in PDS system, with a first-order reaction kinetic constant (k) and total organic carbon (TOC) mineralization efficiency of 0.06 min?1 and 59.67% ± 3.4% within 60 min, respectively. CMK catalyzed PDS system exhibited high degradation efficiencies of five other sulfonamides and three other types of antibiotics, verifying the broad-degradation capacity of antibiotics. Under neutral pH conditions, the optimal catalytic parameters were an initial SDZ concentration of 44.0 mg/L, CMK dosage of 0.07 g/L, and PDS dosage of 5.44 mmol/L, respectively. X-ray photoelectron spectroscopy and Raman spectrum analysis confirmed that the defect structure at edge of CMK and oxygen-containing functional groups on surface of CMK were major active sites, contributing to the high catalytic activity. Free radical quenching analysis revealed that both SO4?? and ?OH were generated and participated in catalytic reaction. In addition, direct electron transfer by CMK to activate PDS also occurred, further promoting catalytic performance. Configuration of SDZ molecule was optimized using density functional theory, and the possible reaction sites in SDZ molecule were calculated using Fukui function. Combining ultra-high-performance liquid chromatography (UPLC)–mass spectrometry (MS)/MS analysis, three potential degradation pathways were proposed, including the direct removal of SO2 molecules, the 14S-17 N fracture, and the 19C-20 N and 19C-27 N cleavage of the SDZ molecule. The study demonstrated that ordered mesoporous carbon could work as a feasible catalytic material for PDS advanced oxidation during removal of antibiotics from wastewater.
- Cao, Di,Chen, Fan,Cheng, Hao,Huang, Cong,Li, Zhi-Ling,Liang, Bin,Nan, Jun,Sun, Kai,Wang, Ai-Jie
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supporting information
(2022/01/26)
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- Ruthenium-Catalyzed Reductive Arylation of N-(2-Pyridinyl)amides with Isopropanol and Arylboronate Esters
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A new three-component reductive arylation of amides with stable reactants (iPrOH and arylboronate esters), making use of a 2-pyridinyl (Py) directing group, is described. The N-Py-amide substrates are readily prepared from carboxylic acids and PyNH2, and the resulting N-Py-1-arylalkanamine reaction products are easily transformed into the corresponding chlorides by substitution of the HN-Py group with HCl. The 1-aryl-1-chloroalkane products allow substitution and cross-coupling reactions. Therefore, a general protocol for the transformation of carboxylic acids into a variety of functionalities is obtained. The Py-NH2 by-product can be recycled.
- Ronson, Thomas O.,Renders, Evelien,Van Steijvoort, Ben F.,Wang, Xubin,Wybon, Clarence C. D.,Prokopcová, Hana,Meerpoel, Lieven,Maes, Bert U. W.
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supporting information
p. 482 - 487
(2019/01/04)
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- A PLA-TiO2 particle brush as a novel support for CuNPs: A catalyst for the fast sequential reduction and: N -arylation of nitroarenes
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The present study describes the synthesis and characterization of dispersible copper nanoparticles on a PLA-TiO2 particle brush and their catalytic efficiency in conducting sequential reactions. The prepared CuNP@PLA-TiO2 was characterized using various techniques like SEM, TEM, EDAX, FT-IR, TGA, XRD and UV-vis spectroscopy. The support controlled the size of the nanoparticles between 2-6 nm and prevented their agglomeration during catalysis. A zeta potential of -70.3 mV was measured for the dispersed catalyst, which indicated its high stability in solution. The nanoparticles were effectively used for the synthesis of biphenyl amines from nitro arenes by sequentially carrying out reduction and N-arylation in a single pot. The short reaction time of N-arylation and recyclability are the hallmark of the developed catalytic system.
- Barot, Nirav,Shaikh, Tauhid,Kaur, Harjinder
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p. 5347 - 5354
(2017/07/11)
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- Product and Mechanism of Gas-phase Pyrolysis of 2-arylidinehydrazinopyrimidines: Interesting Route to Condensed Heterocycles [1]
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Gas-phase pyrolysis of N-arylidine-N′-pyrimidin-2-yl-hydrazine derivatives 1a, 1b, 1c, 1d, 1e gave the corresponding arylnitriles 2a, 2b, 2c, 2d, 2e, 2-aminopyrimidine 3, 3-phenyl-1,2,4-triazolo[4,3-a]pyrimidines 4, 2-phenyl-1,2,4-triazolo[1,5-a]pyrimidines 5, 2,4,5-triphenyl-1H-imidazole 6, and 2,3-diphenylquinoline 7. The analyses of the reaction products are reported and used to elucidate the mechanism of the pyrolytic process.
- Al-Awadi, Sundus A.,Ibrahim, Maher R.,El-Dusouqui, Osman M. E.,Al-Awadi, Nouria A.
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p. 1812 - 1816
(2015/11/09)
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- Polymethylhydrosiloxane derived palladium nanoparticles for chemo- and regioselective hydrogenation of aliphatic and aromatic nitro compounds in water
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Chemo- and regioselective hydrogenation of a wide range of aliphatic, unsaturated, aromatic and heteroaromatic nitro compounds into their corresponding amines has been achieved with highly efficient polysiloxane-stabilised "Pd" nanoparticles on NAP-magnesium oxide supports using an environmentally friendly hydrogenating agent, polymethylhydrosiloxane [PMHS] in water. Highly stable and active Pd nanoparticles were prepared by the reduction of NAP-Mg-PdCl4 with PMHS, which serves as a reducing agent as well as a capping agent. The well-dispersed palladium nanoparticles on NAP-MgO catalysts also exhibit excellent regioselectivity in the hydrogenation of dinitrobenzenes to the corresponding nitroanilines. The catalyst has high durability against sintering during the hydrogenation reaction and can be reused with no loss in its activity. This journal is the Partner Organisations 2014.
- Damodara, Dandu,Arundhathi, Racha,Ramesh Babu, T. Venkata,Legan, Margaret K.,Kumpaty, Hephzibah J.,Likhar, Pravin R.
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p. 22567 - 22574
(2014/06/23)
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- Reaction kinetics in liquid ammonia up to 120°C: Techniques and some solvolysis and substitution reactions
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Liquid ammonia is known to be a useful solvent for aromatic nucleophilic substitution reactions of reactive aromatics. Most of the prior work has been carried out at atmospheric pressure and low temperatures. The purpose of this work is to extend the scope of these studies to less reactive haloaromatic substrates that require elevated temperatures to give useful reaction rates. Equipment has been developed to permit the safe study of reactions in liquid ammonia in small (5 mL) stainless steel tube reactors at temperatures up to 120°C (90 bar). Experimental techniques have been developed to permit meaningful sampling of solutions at high temperature and pressure. Sample capture into closed systems, either into a syringe containing quench solution, or directly into an HPLC sample loop, has been used to overcome problems due to flash precipitation and aerosol formation when sampling from high pressure. Activation parameters for the solvolysis of 4-fluoronitrobenzene have been determined over the temperature range 20° - 120°C, and the rates of solvolysis of 2-chloropyrimidine, 4,6-dichloropyrimidine and 2-chloro-5-trifluoromethylpyridine have been determined at appropriate temperatures. 2-Fluoropyridine is inert to solvolysis even at 120°C. Rates of some nucleophilic substitutions with sodium triazolate and sodium phenoxide have been measured. Useful selectivities towards nucleophilic substitution can be obtained for the reactions examined, and further work is planned to examine the wider scope of these reactions. Copyright 2013 John Wiley & Sons, Ltd. Equipment has been developed to permit the safe study of reactions in liquid ammonia in small (5 mL) stainless steel tube reactors at temperatures up to 120°C (90 bar). Activation parameters for the solvolysis of 4-fluoronitrobenzene have been determined over the temperature range 20° - 120°C, and the rates of solvolysis of 2-chloropyrimidine, 4,6-dichloropyrimidine and 2-chloro-5-trifluoromethylpyridine have been determined at appropriate temperatures. Rates of some aromatic nucleophilic substitutions with sodium triazolate and sodium phenoxide have been measured. Copyright
- Atherton, John H.,Page, Michael I.,Sun, Haifeng
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p. 1038 - 1043
(2014/01/06)
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- The kinetics and mechanisms of aromatic nucleophilic substitution reactions in liquid ammonia
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The rates of aromatic nucleophilic substitution reactions in liquid ammonia are much faster than those in protic solvents indicating that liquid ammonia behaves like a typical dipolar aprotic solvent in its solvent effects on organic reactions. Nitrofluorobenzenes (NFBs) readily undergo solvolysis in liquid ammonia and 2-nitrofluorobenzene is about 30 times more reactive than the 4-substituted isomer. Oxygen nucleophiles, such as alkoxide and phenoxide ions, readily displace fluorine of 4-NFB in liquid ammonia to give the corresponding substitution product with little or no competing solvolysis product. Using the pKa of the substituted phenols in liquid ammonia, the Bronsted βnuc for the reaction of 4-NFB with para-substituted phenoxides is 0.91, indicative of the removal of most of the negative charge on the oxygen anion and complete bond formation in the transition state and therefore suggests that the decomposition of the Meisenheimer σ-intermediate is rate limiting. The aminolysis of 4-NFB occurs without general base catalysis by the amine and the second-order rate constants generate a Bronsted βnuc of 0.36 using either the pKa of aminium ion in acetonitrile or in water, which is also interpreted in terms of rate limiting breakdown of the Meisenheimer σ-intermediate. Nitrobenzene and diazene are formed as unusual products from the reaction between sodium azide and 4-NFB, which may be due to the initially formed 4-nitroazidobenzene decomposing to give a nitrene intermediate, which may then give diazene or be trapped by ammonia to give the unstable hydrazine which then yields nitrobenzene.
- Ji, Pengju,Atherton, John H.,Page, Michael I.
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scheme or table
p. 3286 - 3295
(2011/07/07)
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- Preparation and evaluation of N-sulfinyl dienophiles for asymmetric hetero-Diels-Alder reactions
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(Chemical Equation Presented) A series of N-sulfinyl dienophiles 1c-i has been screened in asymmetric hetero-Diels-Alder reactions using chiral bis(oxazoline)copper(II) and -zinc(II) triflates. The survey pointed out N-sulfine 1c (R = P(=O)(OPh)2) as the most promising N-sulfine regarding yield and stereoselectivity (up to 97% ee). The relative configurations, and in one case the absolute configuration, of the HDA adducts were established by X-ray analysis.
- Endeshaw, Molla Mellese,Hansen, Lars K.,Gautun, Odd R.
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p. 149 - 154
(2008/09/20)
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- PROCESS FOR PRODUCING TETRAALKOXYPROPANE AND DERIVATIVE THEREOF
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In view of the fact that a methyl vinyl ether, which is useful as a starting material for the synthesis of tetraalkoxypropane useful as a skeleton-forming agent having a high reactivity usable as a starting material, etc. for a pharmaceutical and agrochemical intermediates such as a pyrazole derivative or pyrimidine derivative, particularly 1,1,3,3-tetramethoxypropane, is in a gaseous state and difficult to use for industrial production, tetraalkoxypropane useful as a skeleton-forming agent for a pharmaceutical and agrochemical intermediate such as a pyrazole derivative or pyrimidine derivative is easily produced on an industrial scale by using the industrially useable propoxyvinyl ether, as a starting material, without using a gaseous state methyl vinyl ether.
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Page/Page column 7
(2008/06/13)
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- Arylindenopyridines and arylindenopyrimidines and related therapeutic and prophylactic methods
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This invention provides novel arylindenopyridines and arylindenopyrimidines of the formula: wherein R1, R2, R3, R4, and X are as defined above, and pharmaceutical compositions comprising same, useful for treating disorders ameliorated by antagonizing adenosine A2a receptors. This invention also provides therapeutic and prophylactic methods using the instant compounds and pharmaceutical compositions.
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- Selective arylation of exocyclic N-position of 2-pyrimidylnitrenium ion photolytically generated from tetrazolo[1,5-a]pyrimidine in the presence of trifluoroacetic acid
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Photo-reactions of tetrazolo[1,5-a]pyrimidine (1) with benzene (2a) and substituted benzenes (2b-f) in the presence of trifluoroacetic acid (TFA) gave 2-(2-, 3- and 4-substituted anilino)pyrimidines (3-5) together with 2-aminopyridine (6) and biphenyl (7) or diarylmethanes (8b, 8c and 8e). From the effect of heavy-atom solvent on the reactions, it is reasonable to assume that 3-5 are formed via a singlet species, but 6-8 via a triplet species. The intermediacy of 2-pyrimidylnitrenium ion is consistent with the evidence derived by the above effect, by a Hammett plot with p = -2.9 and by effects of solvent nucleophilicity and counter-anions. The selective exocyclic N-arylation giving 3-5 is discussed.
- Takeuchi, Hiroshi,Watanabe, Keiichi
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p. 478 - 484
(2007/10/03)
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- Synthesis and binding behavior of an artificial receptor based on 'upper rim' functionalized calix[5]arene
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A new calix[5]arene possessing two benzoic acid moieties was synthesized as an artificial receptor and its ability of binding to a variety of amine guests was investigated. The structures of the complexes with the mines were proposed by the molecular mechanics calculation using MacroModel V. 4.0.
- Haino, Takeharu,Matsumura, Kazumi,Harano, Tetsuya,Yamada, Kaori,Saijyo, Yoshikazu,Fukazawa, Yoshimasa
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p. 12185 - 12196
(2007/10/03)
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- Fungal and bacterial regioselective hydroxylation of pyrimidine heterocycles
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The bacterium Rhodococcus erythropolis is employed to hydroxylate the anxiolytic lesopitron, and this bacterium, together with Agrobacterium sp. and the fungus Beauveria bassiana, are used to extend the field of hydroxylation of heteroaromatic compounds to a series of unexplored pyrimidines. Of all the substrates investigated, only the carbamate 11a is regioselectively hydroxylated by B. bassiana at the C-5 position of the pyrimidine ring; in contrast, the bacteria are able to regioselectively oxidize, when free, the C-2 and/or C-4 positions of the pyrimidine moiety of all the substrates 1a - 12a up to a maximum of two oxidations.
- Gotor, Vicente,Quiros, Margarita,Ramon, Liz,Frigola, Jordi,Fernandez, Rosa
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p. 6421 - 6432
(2007/10/03)
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- Substituted guanidine and amidine compounds, and fungicidal use
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The present invention relates to novel substituted guanidine and amidine compounds, their preparation and their use in the kill and control of fungal organisms which infest plants.
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- Artificial DNA base pair analogues
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The present invention is directed to new artificial base pairs comprising complementary artificial purines and pyrimidines and methods of using artificial complementary base pairs.
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- Reaction of 2-Dimethylaminomethylene-1,3-diones with Dinucleophiles. VIII. Synthesis of Ethyl and Methyl 2,4-Disubstituted 5-Pyrimidinecarboxylates
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Reaction of ethyl or methyl 2-dimethylaminomethylene-3-oxoalkanoates with N-C-N dinucleophiles such as guanidine, acetamidine or benzamidine afforded in high yields the relative esters of 4-substituted 2-amino-, 2-methyl- or 2-phenyl-5-pyrimidinecarboxylic acids, respectively.These esters were hydrolyzed to the corresponding carboxylic acids, which were converted by heating to 4-substituted 2-pyrimidinamines, 2-methyl or 2-phenylpyrimidines, respectively, generally in excellent yields.The 4-unsubstituted ethyl 2-amino-, 2-methyl- and 2-phenyl-5-pyrimidinecarboxylateswere obtained in moderate yields by reaction of the above dinucleophiles with ethyl 2,2-diformylacetate.These esters were hydrolyzed and the corresponding acids (with the exception of the 2-methyl derivative) were decarboxylated to give 2-pyrimidinamine and 2-phenylpyrimidine in satisfactory yields.
- Schenone, Pietro,Sansebastiano, Laura,Mosti, Luisa
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p. 295 - 305
(2007/10/02)
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- DIAZOTIZATION OF SOME AMINODIAZINE N-OXIDES
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Diazotization of a number of aminopyrazine and aminopyrimidine N-oxides affords intermediate diazonium compounds which can be converted to the corresponding bromo and chloro analogs in the presence of the appropriate halide ions.In some instances, electrophilic aromatic substitution takes place prior to the diazotization step.Nucleophilic halogenation accompanying deoxygenation occurs with 2-aminopyrimidine N-oxide in the same manner as described for some 3-amino-1,2,4-triazine 2-oxides.
- Jovanovic, Misa V.
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p. 2011 - 2018
(2007/10/02)
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- SRN1 Mechanism in Heteroaromatic Nucleophilic Substitution. Reactions Involving Halogenated Pyrimidines, Pyridazines, and Pyrazines
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Reactions of 2-chloropyrimidine (1), 4-chloro-2,6-dimethoxypyrimidine (7), 3-chloro-6-methoxypyridazine (9), and 2-chloropyrazine (14) with a representative series of ketone enolates in liquid ammonia exhibited characteristics consistent with a radical-chain (SRN1) mechanism for substituton.Diazines 1 and 9 showed an unexpected sensitivity to enolate ion structure, with 1 reacting best with tertiary enolates and 9 undergoing substitution most satisfactorily with primary enolates.The order of SRN1 reactivity among the various substrates was found to be 14 > 9 > 7 =ca. 1.Thus 1 and 7 required photostimulation at 35o nm for satisfactory displacemement of chloride, 9 underwent some substitution without illumination, and 14 reacted smoothly in the dark.
- Carver, David R.,Komin, Andrew P.,Hubbard, James S.,Wolfe, James S.
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p. 294 - 299
(2007/10/02)
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- Manufacture of derivatives of malondialdehyde
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Compounds of the general formula EQU1 which may be used in place of malondialdehyde in synthesis reactions are obtained in a one-step reaction form dimethylformamide, phosgene and an alkyl vinyl ether.
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- 2-(Thi)oxo-3-imidazolyl-(2)-tetrahydroimidazoles
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Imidazoles of the formula I STR1 wherein one of the radicals R1 and R2 denotes hydrogen or lower alkyl and the other denotes the nitro group, R3 is lower alkyl, hydroxy-lower alkyl, lower alkoxy-lower alkyl, lower alkyl-sulphonyl-lower alkyl or amino-lower alkyl, R4 is oxo or thioxo, R5 - if R1 is the nitro group - is hydrogen, lower alkyl, hydroxy-lower alkyl, lower alkoxy-lower alkyl, amino-lower alkyl, acyl, aryl or a heterocyclic radical or R5 -- if R2 is the nitro group -- is aryl or a heterocyclic radical, with the exception of an optionally substituted 2-imidazolyl group, and alk is lower alkylene and their therapeutically usable salts, S-oxides, sulphones or N-oxides are useful as agents against amoebae, schistosomes, filariae, trichomonades and bacteria and as intermediates.
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- Pyrimidinoaminoethyl ergoline derivatives
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Pyrimidinoaminoethyl ergoline derivatives of the formula: STR1 wherein R is hydrogen or methyl; R1 and R2 are independently selected from the group consisting of hydrogen, alkyl having 1 to 3 carbon atoms, methoxy and phenyl; R3 is hydrogen, halogen, alkyl and alkoxy each having 1 to 3 carbon atoms, phenyl, nitro, amino, cyano, acylamino, carboxamido and carbalkoxy each having 1 to 3 carbon atoms, trifluoromethyl or --SO2 --Y wherein Y is hydroxyl, amino or methyl and R4 is hydrogen or methoxy are prepared by reacting an ergoline derivative of formula III and a 2-aminopyrimidine anion of formula II STR2
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