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Method for preparing cyclopropylboric acid

A technology of cyclopropyl boronic acid and cyclopropyl bromide, applied in the field of preparing cyclopropyl boronic acid, can solve problems such as potential safety hazards and danger, and achieve the effects of low risk, low cost and high yield

Active Publication Date: 2013-04-17
DALIAN NETCHEM CHIRAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has some defects: this method requires low temperature reaction, and the preparation of the raw material cyclopropyllithium needs metal lithium and solvent ether, which is a dangerous chemical, and there are many safety hazards in procurement, transportation, storage and use.

Method used

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  • Method for preparing cyclopropylboric acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A kind of method for preparing cyclopropyl boronic acid, boronation is with isopropoxy borate pinacol ester, and hydrolysis oxidant is example with potassium permanganate:

[0023] The preparation of the first step raw material cyclopropylmagnesium bromide:

[0024] Under nitrogen protection, add 9.16 g (0.382 mol) of magnesium, 340 mL of tetrahydrofuran, and 2.0 g of cyclopropyl bromide (0.016 mol) into a 500 ml four-necked flask equipped with a mechanical stirrer, a thermometer, and a condenser. Raise the temperature to 50°C and keep warm to initiate the reaction. After the start, control the temperature of the kettle at 40-60°C and add 40g cyclopropyl bromide (0.331mol) dropwise. After the dropwise addition, keep warm for 2 hours and analyze the concentration of Grignard reagent cyclopropylmagnesium bromide. 0.95mol / kg, 347.0g, yield 95%.

[0025] The preparation of the second step cyclopropyl boronic acid:

[0026] Add 67.46g (0.363mol) isopropoxy pinacol borate a...

Embodiment 2

[0028] A kind of method for preparing cyclopropyl boronic acid, boronation is with isopropoxy boric acid pinacol ester, and hydrolysis oxidant is example with potassium periodate:

[0029] The preparation of the first step raw material cyclopropylmagnesium bromide:

[0030] Same as the first step of embodiment 1:

[0031] The preparation of the second step cyclopropyl boronic acid:

[0032] Add 67.46g (0.363mol) isopropoxy pinacol borate and 150ml (1.85mol) tetrahydrofuran to a 1L four-neck flask equipped with a mechanical stirrer, a thermometer, and a condenser tube under nitrogen protection, and add the first Bug Grignard reagent 347.0g (0.330mol), keep warm for 1 to 5 hours after dropping, monitor the gas phase after the reaction is completed, control the room temperature and drop 10% hydrochloric acid aqueous solution to adjust the pH value of the kettle liquid to 1 to 3, and then add potassium periodate 6.84g (0.032mol) was stirred for 2-10 hours, and the reaction was c...

Embodiment 3

[0034] A kind of method for preparing cyclopropyl boronic acid, boronation is with isopropoxy boric acid pinacol ester, and hydrolysis oxidant is example with cerium ammonium nitrate:

[0035] The preparation of the first step raw material cyclopropylmagnesium bromide:

[0036] Same as the first step of embodiment 1:

[0037] The preparation of the second step cyclopropyl boronic acid:

[0038] Add 67.46g (0.363mol) isopropoxy pinacol borate and 150ml (1.85mol) tetrahydrofuran to a 1L four-neck flask equipped with a mechanical stirrer, a thermometer, and a condenser tube under nitrogen protection, and add the first Bug Grignard reagent 347.0g (0.330mol), keep the temperature for 1 to 5 hours after the dropping, gas phase monitoring after the reaction is completed, control the room temperature and drop 10% hydrochloric acid aqueous solution to adjust the pH value of the kettle liquid to 1 to 3, and then add cerium ammonium nitrate 17.54 g (0.032mol) was stirred for 2-10 hours...

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Abstract

The invention discloses a method for preparing cyclopropylboric acid. The method comprises the following steps: reacting cyclopropyl bromide with magnesium reagents to generate cyclopropylmagnesium bromide which then reacts with 1-substituent boronic acid pinacol ester to prepare cyclopropylboric acid. The raw materials for the method are easy to obtain, the operation is easy, the method is safe and environment-friendly, the cost is low, and the yield is high. The innovation includes that hazardous materials such as lithium metal and diethyl ether in the literature are avoided; and cyclopropylmagnesium bromide and 1-substituent boronic acid pinacol ester are taken as the raw material to synthesize cyclopropylboric acid with a high yield under the room temperature condition, therefore the raw material risk is small, the reaction conditions are mild, the yield is high, and the environment is not polluted.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, in particular to a method for preparing cyclopropylboronic acid. Background technique [0002] The currently known synthetic method of cyclopropyl boronic acid basically adopts diethyl ether as solvent, and cyclopropyl lithium is synthesized with boronating reagent. This method has some defects: this method requires low temperature reaction, and the preparation of the raw material cyclopropyllithium needs metal lithium and solvent ether, which is a dangerous chemical, and there are many safety hazards in procurement, transportation, storage and use. Contents of the invention [0003] The object of the present invention is to overcome above-mentioned insufficient problem, provide a kind of method for preparing cyclopropyl boronic acid, generate cyclopropyl magnesium bromide with cyclopropyl bromide and magnesium Grignard reaction, then with 1-substituted boronic acid pinacol ester Th...

Claims

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Application Information

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IPC IPC(8): C07F5/02
Inventor 刘启宾李洪建于双杨兆辉
Owner DALIAN NETCHEM CHIRAL TECH
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