- Preparation method of 2,3-dichloropyridine
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The invention provides a preparation method of 2,3-dichloropyridine. The 2,3-dichloropyridine is prepared by a one-pot method, pyridine alkyl ester serves as a raw material, and synthesis is conductedby a mode of performing chlorination, performing hydrolysis and performing chlorination again; the chlorination is substitution reaction, substitution on a benzene ring is relatively easy, the alkylester group can protect the site of the first-time chlorination reaction to be at 2 position, the hydrolysis reaction is mild in condition and rapid in reaction compared with the prior art, the second-time chlorination is to substitute the hydroxyl, the reaction is easy and the reaction condition is relatively mild. The preparation method provided by the invention is simple in operation, few threewastes are generated in the production process, requirements on equipment are low and the yield is high.
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- Method for preparing 2,3-dichloropyridine
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The invention discloses a method for preparing 2,3-dichloropyridine. The method comprises the following steps that 3-pyridone is dissolved in a caustic alkali water solution, a sodium hypochlorite water solution is dropwise added, and the materials fully react; after the reaction is completed, acid is added to regulate the pH of the system to be neutral or acidic, cooling and filtering are carried out, and crude 2-chloro-3-pyridone is obtained; crude 2-chloro-3-pyridone is dissolved in dimethylformamide, a chloride agent is added, the materials fully react, cooling is carried out after the reaction is completed, water is added to decompose the chloride agent which does not react, the pH of the system is regulated to be neutral or acidic with caustic alkali, filtering is carried out, and 2,3-dichloropyridine is obtained. The method is short in reaction period, simple in production process, stable in reaction, low in production cost and high in product yield.
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Paragraph 0022; 0023; 0024; 0025; 0026; 0027; 0029
(2017/08/28)
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- Cesium carbonate mediated aryl triflate esters' deprotection
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A variety of diversely substituted aryl triflate esters were efficiently deprotected to the parent phenols by exposure to cesium carbonate in toluene. This procedure proved highly compatible with existing functional groups.
- Green, Alice E.,Agouridas, Vangelis,Deniau, Eric
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supporting information
p. 7078 - 7079
(2013/12/04)
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- Efficient synthesis of halohydroxypyridines by hydroxydeboronation
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This paper describes a general method for the synthesis of halohydroxypyridines from novel halopyridinylboronic acids and esters recently described by some of us. Halopyridinylboronic acids and esters have been efficiently hydroxydeboronated under mild conditions by employing hydrogen peroxide or meta-chloroperbenzoic acid. These hydroxylations take place regioselectively without other oxidation (N-oxide formation).
- Voisin, Anne Sophie,Bouillon, Alexandre,Lancelot, Jean-Charles,Rault, Sylvain
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p. 1417 - 1421
(2007/10/03)
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- Method for producing an optically active 1-substituted 2-propanol
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A method for producing an optically active 1-substituted 2-propanol of the following formula 1, which comprises reacting a hydroxy aromatic compound of the following formula 2 with an optically active propylene oxide in the presence of a catalyst:AOH??Formula 2CH3C*H(OH)CH2OA??Formula 1wherein A is a univalent aromatic group, and C* is an asymmetric carbon atom.
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- An efficient facile and selective hydroxylation of nitrogen heterocycles
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Nitrogen heterocycles have been efficiently hydroxylated under mild and neutral conditions by employing Cupric nitrate/phosphate buffer/30%hydrogen peroxide system. The present method afforded the biologically active and important hydroxy heterocycles. Th
- Nasreen, Aayesha,Adapa, Srinivas R.
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p. 501 - 506
(2007/10/03)
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- Total Synthesis of (+/-)-Atpenin B. An Original "Clockwise" Functionalization of 2-Chloropyridine
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(-)-Atpenin B (1) is an antibiotic produced by Penicillim sp.FO-125.The first synthesis of 2,4-dihydroxy-5,6-dimethoxy-3-((2RS,4RS)-2,4-dimethyl-1-oxohexyl)pyridine (atpenin B) (16) is reported.This molecule, which exhibits a pentasubstituted pyridine structure, was prepared from 2-chloropyridine in 13 steps, by metalating and then functionalizing, one after another, all the remaining positions of the pyridine ring.The methodology involves four metalation steps (including metalation of 2,3-dimethoxypyridine and pyridyl N,N-diisopropylcarbamates), one halogen-scrambling step, and one bromine-lithium exchange step.
- Trecourt, Francois,Mallet, Marc,Mongin, Olivier,Queguiner, Guy
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p. 6173 - 6178
(2007/10/02)
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- The use of the cyanomethyl unit as a protecting group for phenols, amines and carbamates
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The use of the cyanomethyl unit as a protecting group for phenols, primary and secondary amines, and carbamates is described. Optimized conditions for formation and hydrolysis of cyanomethyl in the presence of the other hydrogenolysis-sensitive groups such as O- and N-benzyl groups are presented.
- Benarab,Boye,Savelon,Guillaumet
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p. 7567 - 7568
(2007/10/02)
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