- Synthesis method of 3-bromo-5-methylpyridine
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The invention relates to the field of organic chemistry and particularly provides a synthesis method of 3-bromo-5-methylpyridine. The synthesis method includes the steps of: 1) performing a reaction to diethyl malonate and alkaline metal to generate a salt, and dropwise adding a toluene solution of 3-nitro-5-chloropyridine to perform a condensation reaction, and decarboxylating the product under an acidic condition to obtain 3-nitro-5-methylpyridine; 2) performing hydrogenation reduction to the 3-nitro-5-methylpyridine with Pd/C as a catalyst and methanol as a solvent, performing suction filtration and concentrating a filtrate to prepare 3-amino-5-methylpyridine; and 3) performing a reaction to the 3-amino-5-methylpyridine with an acid to generate a salt, and cooling the salt to -10 - 0 DEG C, dropwise adding liquid bromine, and then dropwise adding a sodium nitrite water solution, regulating the pH value of the solution to alkalinity and performing extraction, drying and concentration to obtain the 3-bromo-5-methylpyridine. The synthesis method is mild in reaction conditions, is high in yield, employs easy-to-obtained raw materials, is low in cost, is short in process route and has industrial prospect.
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Paragraph 0024
(2017/10/07)
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- An Alternative Synthetic Approach to 3-Alkylated/Arylated 5-Nitropyridines
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An alternative method for the synthesis of 3-alkylated/arylated 5-nitropyridines was developed involving a three-component ring transformation of 3,5-dinitro-2-pyridone on treatment with aldehyde in the presence of ammonium acetate. This method facilitate
- Le, Song Thi,Asahara, Haruyasu,Nishiwaki, Nagatoshi
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p. 8856 - 8858
(2015/09/15)
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- Preparation of nitropyridines by nitration of pyridines with nitric acid
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Preparation of nitropyridines by nitration of pyridines with nitric acid was discussed. Trifluoroacetic anhydride was chilled in an ice bath and the pyridine or substituted pyridines were slowly added and stirred at chilled conditions for 2 h. Relative amounts of the reactants were required for the nitration of pyridine were characterized by 1H and Nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. It was observed that the yields of β-nitropyridines obtained using the standard protocol were generally higher than those obtained using N2O3.
- Katritzky, Alan R.,Scriven, Eric F. V.,Majumder, Suman,Akhmedova, Rena G.,Vakulenko, Anatoliy V.,Akhmedov, Novraz G.,Murugan, Ramiah,Abboud, Khalil A.
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p. 538 - 541
(2007/10/03)
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- The synthesis of β-nitropyridine compounds
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Pyridine and a number of substituted pyridines have been nitrated by reaction with N2O5 followed by reaction with an aqueous solution of SO2xH2O or NaHSO3. The dependence of the yields on the pH of the aqueous reaction medium, on the concentration of SO2xH2O-HSO3-, on addition of methanol to the aqueous phase, and on the reaction temperature were investigated. The yields obtained with NaHSO3 were: 3-nitropyridine 77%, 2-methyl-5-nitro-pyridine 36%, 3-methyl-5-nitropyridinc 24%, 3-acetyl-5-nitropyridine 18%, 5-nitropyridine-3-carboxylic acid 15%, 3-chloro-5-nitropyridine 11%, 4-methyl-3-nitropyridine 39%, 4-acetyl-3-nitropyridine 67%, 4-cyano-3-nitropyridine 45%, 4-phenyl-3-nitropyridine 68%, 4-formyl-3-nitropyridine 62% (from reaction in liquid SO2), 3-nitropyridine-4-carboxylic acid 48%, methyl 3-nitropyridine-4-carboxylate 75%, 2,3-dimethyl-5-nitropyridine 37%, 2,4-dimethyl-5-nitropyridine 64%, 3-nitroquinoline 10% and 4-nitroisoquinoline 42%.
- Bakke, Jan M.,Ranes, Eli,Riha, Jaroslav,Svensen, Harald
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p. 141 - 144
(2007/10/03)
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- Nitropyrimidinones; synthetic equivalents of diformylamine and nitromalonaldehyde
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Reactions of two isomeric nitropyrimidinones with bidentate enolate anions were studied. When 3-methyl-5-nitropyrimidin-4(3H)-one (1) was employed, ring transformation proceeded to give pyridin-4(1H)-ones 3 functionalized at the 3- or 5-positions. This pyrimidin-4-one 1 behaved as an activated diformylamine HN(CHO)2. 1-Methyl-5-nitropyrimidin-2(1H)-one (2) afforded polyfunctionalized bicyclo[3.3.1]nonene derivatives 7 and 8 and/or p-nitrophenol derivatives 9. In this case, pyrimidin-2-one 2 acted as the synthetic equivalent of unstable O2NCH(CHO)2. These two nitropyrimidinones are valuable intermediates for the synthesis of polyfunctionalized compounds.
- Nishiwaki,Tohda,Ariga
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p. 1277 - 1280
(2007/10/03)
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- Nitration of Aromatic and Heteroaromatic Compounds by Dinitrogen Pentaoxide
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Nitration of benzene and monosubstituted benzenes in liquid SO2 by dinitrogen pentaoxide at - 11 deg C gave the corresponding nitroarenes with substitution patterns similar to those obtained by nitrations with HNO3-H2SO4.For acetophenone an o/m ratio of 0.94 was obtained.The yields were dependent on the substituents.With a 1:1 ratio of arene: N2O5 the yields varied from 73percent for toluene to 0.4percent for nitrobenzene as substrates.From competition experiments and the nitration of bibenzyl it was concluded that the reaction was faster than the macroscopic rate of mixing.The qualitative order of reactivity for PhX was X = OCH3>CH3>H>Cl>CH3CO>NO2.Nitration with N2O5 in liquid CO2 gave similar results.Nitration of pyrimidine, pyrrole, imidazole and indole with N2O5-SO2 gave no nitrated products.With thiophene, 2- (34percent) and 3-nitrothiophene (5percent) together with 2,4-(16percent) and 2,5-dinitrothiophene (8percent) were obtained.With pyridine, mono- and di-methylpyridines, quinoline, isoquinoline and 4-phenylpyridine nitration of the pyridine ring was obtained.The yields varied from ca. 70percent to 16percent, except for 3,5-, 2,5- and 2,6-dimethylpyridine for which only traces of nitro-dimethylpyridines were obtained.The reaction with the pyridines appears to be intramolecular both in the SO2 phase and in the water phase used for quenching the reaction.The reaction was proposed to proceed by a complex formed in liquid SO2:
- Bakke, Jan M.,Hegbom, Ingrid,Oevreeide, Elin,Aaby, Kjersti
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p. 1001 - 1006
(2007/10/02)
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