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Synthetic method of 1-methyl 4-pyrazole pinacol ester

A synthesis method and pinacol ester technology are applied in the field of preparation of 1-methyl 4-pyrazole pinacol ester, can solve problems such as being limited to laboratory preparation and cannot be produced on a large scale, and achieve process improvement and optimization. The effect of processing technology and raw materials is cheap

Inactive Publication Date: 2012-09-26
SHANGHAI SYNTHEALL PHARM CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The method for effectively preparing 1-methyl 4-pyrazole pinacol ester solves the problem that the existing 1-methyl 4-pyrazole pinacol ester is limited to laboratory preparation and cannot be produced on a large scale

Method used

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  • Synthetic method of 1-methyl 4-pyrazole pinacol ester

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Experimental program
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Effect test

Embodiment 1

[0019] Step 1: Under mechanical stirring, add (1.22mol, 100g) SM and 2L anhydrous tetrahydrofuran into the three-necked flask, and cool the solution to -60~-70 o C, slowly add (1.34 mol, 535mL) n-butyllithium (2.5M n-hexane solution) dropwise, and control the dropping temperature not to exceed -60 o C, after the addition is completed at -60~-70 o C reacted for 3 hours, slowly added (1.34 mol, 252g) triisopropyl borate dropwise to the reaction solution, and controlled the dropping temperature not to exceed -60 o C, continue at -60~-70 o C reacted for 3h, slowly warming up to room temperature, reacted at room temperature for 12h, and took a sample to detect that the reaction was qualified. Cool down to 0~10 o C, 2L of saturated ammonium chloride aqueous solution was added dropwise to the reaction solution, the pH was adjusted to 5 with 2N hydrochloric acid solution, and the layers were separated. The aqueous layer was extracted three times with 2 L of ethyl acetate, and the ...

Embodiment 2

[0022] Step 1: Under mechanical stirring, add (1.22mol, 100g) SM and 2L anhydrous tetrahydrofuran into the three-necked flask, and cool the solution to -60~-70 o C. Slowly add (1.46mol, 585mL) n-butyl lithium (2.5M) dropwise, and control the dropping temperature not to exceed -60 o C, after the addition is completed at -60~-70 o C reacted for 2.5h, slowly added (1.34 mol, 252g) triisopropyl borate dropwise to the reaction solution, and controlled the dropping temperature not to exceed -60 o C, continue at -60~-70 o C reacted for 2.5h, slowly warming up to room temperature, reacted at room temperature for 10h, and took a sample to detect that the reaction was qualified. Cool down to 0~10 o C, 2L of saturated ammonium chloride aqueous solution was added dropwise to the reaction solution, the pH was adjusted to 5 with 2N hydrochloric acid solution, and the layers were separated. The aqueous layer was extracted three times with 2 L of ethyl acetate, and the organic layers were...

Embodiment 3

[0025] Step 1: Under mechanical stirring, add (1.22mol, 100g) SM and 2L anhydrous tetrahydrofuran into the three-necked flask, and cool the solution to -60~-70 o C, slowly add (1.34 mol, 535mL) n-butyllithium (2.5M) dropwise, and control the dropping temperature not to exceed -60 o C, after the addition is completed at -60~-70 o C reacted for 3 hours, slowly added (1.34 mol, 252g) triisopropyl borate dropwise to the reaction solution, and controlled the dropping temperature not to exceed -60 o C, continue at -60~-70 o C reacted for 3 hours, slowly warming up to room temperature, reacted for 12 hours at room temperature, and took a sample to detect that the reaction was qualified. Cool down to 0~10 o C, 2L of saturated ammonium chloride aqueous solution was added dropwise to the reaction solution, the pH was adjusted to 6 with 2N hydrochloric acid solution, and the layers were allowed to stand. The aqueous layer was extracted three times with 2 L of ethyl acetate, and the o...

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Abstract

The invention relates to a synthetic method of 1-methyl 4-pyrazole pinacol ester. The biggest advantage of the invention is that the technology is greatly improved; and the problem that the preparation technology of 1-methyl 4-pyrazole pinacol ester is limited in a laboratory and there is no large-scale production is solved. The technical scheme provided by the invention is as follows: the synthetic method of 1-methyl 4-pyrazole pinacol ester comprises The following steps of: Step 1, performing a reaction between 1-methyl 4-pyrazole and triisopropyl borate under the action of n-butyllithium to obtain an intermediate A; and Step 2, performing a reaction between the intermediate A and pinacol under the action of magnesium sulfate to obtain the target product 1-methyl 4-pyrazole pinacol ester. The obtained 1-methyl 4-pyrazole pinacol ester is an important intermediate commonly-used in pharmaceutical chemistry.

Description

technical field [0001] The invention relates to a preparation method of 1-methyl 4-pyrazole pinacol ester. Background technique [0002] The preparation method of 1-methyl 4-pyrazole pinacol ester has following two kinds at present, method one: take 1-methylpyrazole and isopropanol pinacol borate as starting raw material, and n-butyllithium at -78 o C reaction, quenched and washed with water, extracted with dichloromethane, concentrated to obtain the thick product 1-methyl 4-pyrazole pinacol ester ( Ref: WO2009158376 ). The synthetic route is as follows: [0003] [0004] This synthetic route is not suitable for mass production on an industrial scale, for the following reasons: the dichloromethane solution obtained by extraction is directly concentrated to dryness to obtain a crude product, which is not suitable for industrial production. The crude product was used directly in the next step without purification. [0005] Method two: take 1-methylpyrazole and pinacol ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F5/02
Inventor 黄平贾默刘森秀肖丁吉郭劲松于庆陈民章唐苏翰
Owner SHANGHAI SYNTHEALL PHARM CO LTD
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