Preparation method of nitrobenzyl bromide

A technology of o-nitrobenzyl bromide and o-nitrotoluene, which is applied in the field of preparation of o-nitrobenzyl bromide, can solve the problems of slow reaction rate and unsuitability for industrial production, and achieve the advantages of simple operation, high yield and low content Effect

Active Publication Date: 2018-05-25
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[CN103641722A] such as Liu Fang [CN103641722A] adopt hydrogen bromide/hydrogen peroxide solution as bromination reagent, azobisisobutyronitrile is catalyst, polyethylene glycol PEG600 is phase tr

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  • Preparation method of nitrobenzyl bromide
  • Preparation method of nitrobenzyl bromide

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Experimental program
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Embodiment 1

[0019] Weigh 6.85 grams of o-nitrotoluene and dissolve in 130 grams of dichloromethane, add 13.16 grams of 40% hydrogen bromide solution, 0.82 grams of azobisisobutyronitrile, and 0.81 grams of anhydrous ferric chloride to the system, and stir Heat to reflux, add 7.37 g of 30% hydrogen peroxide solution dropwise at 1 drop / min, stir and reflux for 2 hours, cool to room temperature, and separate the organic phase, which is o-nitrobenzyl bromide. As detected by HPLC, the yield was 86.31%, and the purity was 89.11%.

Embodiment 2

[0021] Weigh 6.85 grams of o-nitrotoluene and dissolve in 130 grams of dichloromethane, add 15.19 grams of 40% hydrogen bromide solution, 0.82 grams of azobisisobutyronitrile to the system, add 0.89 grams of cobalt acetate, stir and heat to Reflux, and dropwise add 8.50 g of 30% hydrogen peroxide solution at 2 drops / min, stir and reflux for 2 hours, cool to room temperature, and separate the organic phase, which is o-nitrobenzyl bromide. As detected by HPLC, the yield was 82.77%, and the purity was 91.11%.

Embodiment 3

[0023] Weigh 6.85 grams of o-nitrotoluene and dissolve in 130 grams of dichloromethane, add 17.21 grams of 40% hydrogen bromide solution, 0.82 grams of azobisisobutyronitrile to the system, add 0.68 grams of zinc chloride, stir and heat to reflux, and dropwise added 9.63 g of 30% hydrogen peroxide solution at 2 drops / min, stirred and refluxed for 2 hours, cooled to room temperature, and separated the organic phase, which was o-nitrobenzyl bromide. As detected by HPLC, the yield was 81.72%, and the purity was 93.83%.

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Abstract

The invention discloses a preparation method of nitrobenzyl bromide. The preparation method comprises the following steps of: step 1, dissolving ortho-nitrotoluene in halohydrocarbon, sequentially adding a hydrogen bromide solution, an initiator and lewis acid, continuing stirring and heating for backflow reaction, and step 2, dropwise adding a hydrogen peroxide solution into a reaction system instep 1 at a speed of 1-2 drops per min, after the backflow reaction for 1-3h, performing natural cooling, stopping stirring, and performing separation to form an organic phase, namely nitrobenzyl bromide. The method takes ortho-nitrotoluene as a raw material and hydrogen bromide as a bromine source; the hydrogen peroxide solution is added as an oxidant; the initiator and lewis acid are added for ortho-nitrotoluene bromination reaction to generate nitrobenzyl bromide; the preparation method is easy and simple to operate and high in yield; and a content of a byproduct, namely o-nitrocyclite is low.

Description

technical field [0001] The invention relates to the field of preparation of o-nitrobenzyl bromide, in particular to a preparation method of o-nitrobenzyl bromide. Background technique [0002] O-nitrobenzyl bromide, also known as 2-nitrobenzyl bromide, English name: 2-Nitrobenzyl bromide, is an important intermediate for the synthesis of a new broad-spectrum fungicide - pyraclostrobin, and its structural formula is as follows: [0003] [0004] O-nitrobenzyl bromide is an organic fine chemical intermediate, which is widely used in organic synthesis of medicine, pesticides, dyes, etc. In the field of medicine, o-nitrobenzyl bromide is an important intermediate in the synthesis of cardiovascular disease drugs such as nifedipine, nisoldipine, and encaramide, and can be used to synthesize o-nitrostyrenes and o-nitrocinnamic acids. . In the field of pesticides, o-nitrobenzyl bromide is a key intermediate in the synthesis of pyraclostrobin and other pesticides, and it is also...

Claims

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Application Information

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IPC IPC(8): C07C201/12C07C205/11
CPCC07C201/12C07C205/11
Inventor 王明亮王慧敏彭景杨闪光刘晶晶
Owner SOUTHEAST UNIV
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