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Preparation method for 2-fluoropyridine-4-boric acid

A technology for fluoropyridine and boric acid, applied in the field of preparing 2-fluoropyridine-4-boronic acid, can solve the problems of low temperature, large influence of bromine equipment, and high cost of raw materials, and achieve the effects of easier temperature, easy temperature control, and cheap raw materials

Inactive Publication Date: 2015-04-01
DALIAN NETCHEM CHIRAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Disadvantages of the existing method: 1. The temperature required for the reaction is extremely low, which needs to be below -78°C; 2. The bromine in the required raw materials has a great impact on the equipment; 3. The cost of raw materials is relatively high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] In the first step, add 100mL tetrahydrofuran and 51.5g diisopropylamine (0.51mol, 1.1eq) to a 1L four-neck flask under nitrogen protection, drop the temperature to -30°C and add 31.7g n-butyllithium (0.51mol, 1.1eq) dropwise , stirring for 1h after dropping, temperature control T≤-55°C, 45g of 2-fluoropyridine (0.46mol, 1eq) was added dropwise, reacted for 4h at T≤-55°C, added 117.8g of iodine (0.46mol, 1eq), and reacted 2h. Add dropwise 200mL sodium bisulfite aqueous solution to quench the reaction, separate the liquids, wash the organic phase with 200mL saturated brine, separate the liquids and concentrate the organic layer to obtain the crude product, and separate it by column chromatography with a certain proportion of developer to obtain intermediate A, 71.3 g, yield 68.9%, purity 97%;

[0028] In the second step, add 100mL tetrahydrofuran and 35.5g diisopropylamine (0.35mol, 1.1eq) to a 1L four-neck flask under nitrogen protection, drop the temperature to -30°C a...

Embodiment 2

[0031] In the first step, add 100mL tetrahydrofuran and 34.4g diisopropylamine (0.34mol, 1.1eq) to a 1L four-neck flask under nitrogen protection, drop the temperature to -30°C and add 21.8g n-butyl lithium (0.34mol, 1.1eq) dropwise , Stir for 1h after dropping, control temperature T≤-55°C, add 30g of 2-fluoropyridine (0.46mol, 1eq) dropwise, react for 4h at T≤-55°C, add 79g of iodine (0.31mol, 1eq), react for 2h . Add dropwise 150mL sodium bisulfite aqueous solution to quench the reaction, separate the liquids, wash the organic phase with 200mL saturated brine, separate the liquids and concentrate the organic layer to obtain the crude product, and separate it by column chromatography with a certain proportion of developer to obtain intermediate A, 44.8 g, yield 65%, purity 96.4%;

[0032] In the second step, add 100mL tetrahydrofuran and 22.2g diisopropylamine (0.22mol, 1.1eq) to a 1L four-necked flask under nitrogen protection, drop the temperature to -30°C and add 14.1g n-...

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PUM

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Abstract

The invention discloses a preparation method for 2-fluoropyridine-4-boric acid. The preparation method comprises the following steps: firstly, reacting 2-fluoropyridine with iodine in the presence of LDA (lithium diisopropylamide) to obtain an intermediate A; secondly, reacting the intermediate with water in the presence of LDA to obtain an intermediate B; thirdly, reacting the intermediate B with triisopropyl borate in the presence of n-butyl lithium to obtain the target product-2-fluoropyridine-4-boric acid. According to the preparation method, raw materials are simple and easily available, the process is safe and reliable, and the target product-2-fluoropyridine-4-boric acid is an important common intermediate in pharmaceutical chemistry.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, in particular to a method for preparing 2-fluoropyridine-4-boronic acid. Background technique [0002] 2-fluoropyridine-4-boronic acid has important applications in chemical and pharmaceutical fields. The existing preparation method uses 2-fluoro-4-bromopyridine as a raw material, uses n-butyllithium and borate to react at -78°C, and obtains the product after purification. Disadvantages of the existing method: 1. The temperature required for the reaction is extremely low and must be below -78° C.; 2. The bromine in the required raw materials has a great impact on the equipment; 3. The cost of the raw materials is relatively high. Contents of the invention [0003] The present application aims to provide an effective method for synthesizing 2-fluoropyridine-4-boronic acid, the specific technical scheme is as follows. [0004] The synthetic method of 2-fluoropyridine-4-b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F5/02
CPCC07F5/025
Inventor 胡超平郑鹏
Owner DALIAN NETCHEM CHIRAL TECH
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