- Preparation method of 2-hydroxy-6-trifluoromethylpyridine
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The invention provides a preparation method of 2-hydroxy-6-trifluoromethylpyridine. The method comprises the following steps of: carrying out Grignard reaction on trifluorohalomethane and magnesium powder to prepare a Grignard reagent; reacting the obtained Grignard reagent with 1, 5-glutaric acid diester, and then acidifying to obtain 4-trifluoroacetyl butyrate; then, carrying out cyclization reaction on the 4-trifluoroacetyl butyrate and ammonia to obtain 6-trifluoromethyl-3, 4-dihydropyridine-2-ketone; and then carrying out an oxidation reaction to obtain the 2-hydroxy-6-trifluoromethylpyridine. The raw materials used in the method are cheap, easy to obtain and low in cost; the steps are simple, and the target product can be prepared by only two steps; the operation is simple and easy for industrial operation; reaction conditions are mild and easy to realize; less wastewater is generated, and the method is green, safe and environment-friendly; and the related raw materials and intermediate products are stable, the reaction selectivity is high, byproducts are few, the yield and purity of the target product are high, and the method is suitable for industrial production.
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Paragraph 0064-0066; 0081-0087
(2021/07/31)
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- Concise synthesis of ω-fluoroalkylated ketoesters. A building block for the synthesis of six-, seven-, and eight-membered fluoroalkyl substituted 1,2-diaza-3-one heterocycles
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A concise and general synthetic route toward the small and medium-sized fluoroalkyl substituted 1,2-diaza-3-one heterocyclic ring skeletons via a sequential reaction of condensation and ring-closure reaction of ω-fluoroalkylated ketoesters 4 with hydrazin
- Wan, Wen,Hou, Jie,Jiang, Haizhen,Wang, Yangli,Zhu, Shizheng,Deng, Hongmei,Hao, Jian
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experimental part
p. 4212 - 4219
(2009/09/30)
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- Absolute rate constants for the addition of the 2- (methoxycarbonyl)propan-2-yl and the 3,3,3-trifluoracetonyl radicals to alkenes in solution
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Absolute rate constants and some of their Arrhenius parameters were obtained by time-resolved electron spin resonance (ESR) spectroscopy for the addition of the 2-(alkoxycarbonyl)propan-2-yl and 3,3,3-trifluoroacetonyl (= 3,3,3-trifluoro-2-oxopropyl) radicals to a variety of mono- and 1,1- disubstituted alkenes. Their analysis shows that the addition of 2- (alkoxycarbonyl)propan-2-yl is mainly governed by the exothermicity of the reaction with slight modifications by nucleophilic and electrophilic effects giving rise to an overall ambiphilic behavior. In contrast, large electrophilic polar effects dominate the addition of the 3,3,3- trifluoroacetonyl (= 3,3,3-trifluoro-2-oxopropan-2-yl) radical, as it is expected from its large electron affinity. For both radicals, the activation energies are well-predicted by analytic equations for the enthalpic and polar terms. A comparison of the rate data of 2-(alkoxycarbonyl)propan-2-yl with the homo- and copolymerization rate constants of the propagating radical of methyl methacrylate shows that the additions of these structurally related low- and high-molecular-weight radicals to alkenes are governed by very, similar effects.
- Zytowski, Torsten,Knuehl, Bernhard,Fischer, Hanns
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p. 658 - 675
(2007/10/03)
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