13466-35-8Relevant articles and documents
Simple preparation method of 2,3-dichloropyridine
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Paragraph 0046-0051; 0061-0062, (2020/03/03)
The invention provides a simple preparation method of 2,3-dichloropyridine. According to the method, 2-piperidone(II) is used as a raw material, 1,3,3-trichloro-2-piperidone (III) is prepared througha chlorination reaction, then hydrogen chloride is eliminated to obtain 3-chloro-2-hydroxypyridine (IV), and then the 2,3-dichloropyridine (I) is prepared through a substitution reaction with a chlorination reagent. Through the method, the raw material is low in price and easy to obtain, the cost is low, the reaction intermediate and the raw material are stable, operation is safe, easy and convenient to perform, a small amount of wastewater is generated, the environment is protected, the reaction selectivity is high, the quantity of side reactions is small, the product yield and purity are high, and the method is suitable for industrial production.
Preparation method of 2,3-dichloropyridine
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Paragraph 0050-0058; 0066; 0067; 0069; 0070, (2020/03/03)
The invention provides a preparation method of 2,3-dichloropyridine. The method comprises the following steps: preparing 2,3-dichloropyridine through an intermediate product 2-hydroxy-3-chloropyridine; preparing 3,3-dichloro-2-piperidone through a chlorination reaction by using 2-piperidone as a raw material; then preparing 2-hydroxy-3-chloropyridine through an elimination and oxidation reaction;and finally preparing the 2,3-dichloropyridine through a substitution reaction under action of the obtained 2-hydroxy-3-chloropyridine and a chlorination reagent. The method has the advantages of cheap and easily obtained raw materials, low cost, stable reaction intermediate and raw materials, safe and simple operation, less waste water generation, environmental protection, high reaction selectivity, few side reactions, and high product yield and purity, and is suitability for industrial production.
Organocatalyzed Enantioselective Michael Addition of 2-Hydroxypyridines and α,β-Unsaturated 1,4-Dicarbonyl Compounds
Wu, Yu-Chun,Jhong, Yi,Lin, Hui-Jie,Swain, Sharada Prasanna,Tsai, Hui-Hsu Gavin,Hou, Duen-Ren
, p. 4966 - 4982 (2019/11/03)
The framework of 2-pyridones is prevalent in biologically and medicinally important molecules. Here we report that chiral N-substituted 2-pyridones were prepared by enantioselective, organocatalytic aza-Michael additions of halogenated 2-hydroxypyridines (pyridin-2(1H)-ones) to α,β-unsaturated-1,4-dketones or 1,4-ketoesters. The reactions were optimized by the choice of solvents and systematic screening of Cinchona alkaloid-based bifunctional catalysts to achieve excellent yields and enantioselectivities (up to 98% yield and >99% ee). Density functional theory calculations provided rationales for the observed enantioselectivity. Formal synthesis of a human rhinovirus protease inhibitor was achieved using the chiral Michael adduct generated by this method. (Figure presented.).
Preparation method of 2,3-dichloropyridine
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Paragraph 0077, (2018/06/15)
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.
Synthesis of α-carbolines starting from 2,3-dichloropyridines and substituted anilines
Hostyn, Steven,Van Baelen, Gitte,Lemiere, Guy L. F.,Maes, Bert U. W.
supporting information; experimental part, p. 2653 - 2660 (2009/08/14)
9H-α-Carbolines have been prepared via consecutive intermolecular Buchwald-Hartwig reaction and Pd-catalyzed intramolecular direct arylation from commercially available 2,3-dichloropyridines and substituted anilines. The combination of a high reaction temperature (180°C) and the use of DBU were found to be crucial for the intramolecular direct arylation reactions of the 3-chloro-N-phenylpyridin-2-amines as no reaction was observed at 120°C and 180°C using different inorganic and other organic bases. On the other hand, nitrogen-methylated pyridine analogues of these substrates {N-[3-chloro-1- methylpyridin-2(1H)-ylidene]anilines} do undergo ring closure at 120°C, with K3PO4 as base, affording the respective 1-methyl-1H-α-carbolines in good yields.
Pyridine hydrochloride: A new reagent for the synthesis of o-chloro hydroxy derivatives in pyridine and quinoline series
Mongin, Florence,Mongin, Olivier,Trecourt, Francois,Godard, Alain,Queguiner, Guy
, p. 6695 - 6698 (2007/10/03)
Pyridine hydrochloride has been widely used in the cleavage of ethers. It is shown herein that his reagent is also efficient for the synthesis of chloro compounds starting from the corresponding bromo derivatives in π-deficient series such as pyridine and quinoline. Thus, for example, 7-bromo-8-hydroxyquinoline was almost quantitatively converted into 7-chloro-8-hydroxyquinoline. The scope of the reaction has been studied.
