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Preparation method of 3-fluoroalkyl-1H-pyrazole-4-formic ester

A fluoroalkyl and formate technology, applied in the field of organic compound preparation, can solve the problems of low regioselectivity and yield, expensive and difficult raw materials, limited application scope, etc., and achieves mild reaction conditions and substrate universality. Good, high-purity effects

Inactive Publication Date: 2016-04-06
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these synthetic methods have problems such as expensive and difficult to obtain raw materials, many reaction steps, cumbersome operations, low regioselectivity and low yield, which undoubtedly limit their application range.

Method used

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  • Preparation method of 3-fluoroalkyl-1H-pyrazole-4-formic ester
  • Preparation method of 3-fluoroalkyl-1H-pyrazole-4-formic ester
  • Preparation method of 3-fluoroalkyl-1H-pyrazole-4-formic ester

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preparation example Construction

[0018] The invention provides a preparation method of 3-fluoroalkyl-1H-pyrazole-4-carboxylate, comprising:

[0019] Mix and react the 3-nitroacrylate shown in formula (I), the fluoroalkyl diazo compound shown in formula (II), catalyst, and basic compound in an organic solvent to obtain the compound shown in formula (III) 3-fluoroalkyl-1H-pyrazole-4-carboxylate;

[0020]

[0021]

[0022] Among them, R f is difluoromethyl, trifluoromethyl or pentafluoroethyl; R is methyl, ethyl, n-propyl, butyl, phenyl or benzyl.

[0023] The preparation method provided by the invention has simple operation steps, mild reaction conditions, high yield, good substrate universality and high purity of the product.

[0024] Above-mentioned reaction equation is as follows:

[0025]

[0026] Among them, R f Preference is given to difluoromethyl, trifluoromethyl or pentafluoroethyl.

[0027] R is preferably methyl, ethyl, n-propyl, butyl, phenyl or benzyl.

[0028] The catalyst is prefer...

Embodiment 13- 3

[0038] Preparation of Example 13-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester

[0039]

[0040] Weigh Ag into a dry 100mL Schlenk reaction flask 2 O (0.17g, 0.75mmol), Na 3 PO 4 (0.12g, 0.75mmol), ethyl 3-nitroacrylate (0.73g, 0.5mmol), replace argon 3 times, add CF to the system 3 CHN 2 THF solution (0.2M, 25mL), stirred at room temperature for 3h. The reaction was complete as monitored by TLC, the metal and inorganic salts in the system were removed by filtration, the filter residue was washed with ethyl acetate, the organic phases were combined, the solvent was evaporated under reduced pressure, the residue was dissolved in dichloromethane, washed with saturated ammonium chloride solution, anhydrous sodium sulfate Drying, column chromatography (eluent: petroleum ether / ethyl acetate=10 / 1~5 / 1) can obtain target product 3-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester 0.65g, The yield was 72%, and the high performance liquid chromatography (HPLC...

Embodiment 23- 3

[0045] Preparation of Example 23-trifluoromethyl-1H-pyrazole-4-carboxylic acid methyl ester

[0046]

[0047] Using the same method as in Example 1, using silver carbonate as a catalyst, sodium carbonate as a base, and dichloromethane as a solvent, 3-methyl nitroacrylate, silver carbonate, sodium carbonate and 2,2,2-trifluorodiazoethyl Alkanes were mixed in a molar ratio of 1 / 3 / 3 / 8, reacted at 40°C for 12h, and synthesized 3-trifluoromethyl-1H-pyrazole-4-carboxylic acid methyl ester, and the aftertreatment was the same as in Example 1, with a yield of 70 %, high performance liquid chromatography (HPLC) purity of 99%.

[0048] The structure of the product was detected by nuclear magnetic resonance, and the results were as follows:

[0049] 1 HNMR (400MHz, CDCl 3 )δ13.32(s,1H), 8.17(s,1H), 4.18(s,3H).

[0050] 19 FNMR (376MHz, CDCl 3)δ-61.79(s).

[0051] 13 CNMR (100MHz, CDCl 3 ) δ 162.2, 141.9 (q, J=37.9Hz), 138.7, 122.1 (q, J=268.0Hz), 112.5, 59.6.

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Abstract

The invention provides a preparation method of 3-fluoroalkyl-1H-pyrazole-4-formic ester. Compared with the prior art, the preparation method comprises the steps of mixing 3-nitro acrylate shown in the formula (I), a fluoroalkyl diazo compound shown in the formula (II), a catalyst, an alkali compound in an organic solvent, and reacting to obtain the 3-fluoroalkyl-1H-pyrazole-4-formic ester shown in the formula (III). The preparation method provided by the invention is simple in operating steps, mild in reaction condition, high in yield, good in universality of a substrate, and meanwhile a product has higher purity.

Description

technical field [0001] The invention relates to the technical field of organic compound preparation, in particular to a preparation method of 3-fluoroalkyl-1H-pyrazole-4-carboxylate. Background technique [0002] 3-Fluoroalkyl-1H-pyrazole-4-carboxylate is the core structural unit of a variety of physiologically active molecules, for example, the fungicide Penthiopyrad (A.K.Culbreath et al., Pest.Manag.Sci.2009,65-66. ), Fluxapyroxad (S.Strathmannetal., Phytopathology 2011, 101-172.), Isopyrazam (T.L.Harpetal., Asp.Appl.Biol. 2011, 106-113.), etc. Therefore, it has important application value in the field of medicine and pesticide. [0003] The method of the reported synthetic 3-fluoroalkyl-1H-pyrazole-4-formic acid ester mainly utilizes the condensation reaction (M.J.Graneto, W.G.Phillips, WO9212970(1992) of α-alkene β-ketoester and hydrazine ); S. Pazenok, WO2009112157 (2009); S. Guillou et al., Tetrahedron 2011, 67, 8451-8457; Santos Fustero, et al., Chem. Rev. 2011, 111...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/14
CPCC07D231/14
Inventor 马军安陈振郑艳
Owner TIANJIN UNIV
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