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Novel method for preparing 3-iodo-2-bromotoluene

A novel technology of bromotoluene, which is applied in the field of preparing 3-iodo-2 bromotoluene, can solve problems such as difficult centrifugation, troublesome post-reduction treatment, and potential safety hazards, and achieves wide and easy-to-obtain raw material sources, simple reagents, and easy operation. easy effect

Pending Publication Date: 2021-08-06
河北唯达生物医药产业技术研究有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the traditional preparation of 3-iodo-2-bromotoluene, iron powder is usually used for nitro reduction, so the post-reduction treatment is very troublesome, centrifugation is not easy, and a large amount of iron sludge will be generated, the amount of solid waste is relatively large, and there are potential safety hazards

Method used

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  • Novel method for preparing 3-iodo-2-bromotoluene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Put 2-amino-3-nitrotoluene (21.8kg), water (130.9kg), and dioxane (67.4kg) into the reaction kettle, and the brown turbid liquid was heated to reflux, and 40% hydrogen was added dropwise under reflux Bromic acid (97.1kg), dropwise. Keep warm for 2 hours, cool down, cool down to 0-20°C, control at 0-20°C, add sodium nitrite solution (9.9kg / 87.3kg) dropwise, after dropping, keep warm for 2 hours, and configure potassium bromide, water, 40% at the same time Hydrobromic acid solution (23.7kg / 130.9kg / 97.1kg), lowered to 0-20°C for later use. Add dropwise to potassium bromide, water, in the system of 40% hydrobromic acid solution (a large amount of foams are generated in the process) after the insulation is completed. After the dropwise addition, keep warm at 0-5°C for 30-60 minutes, raise the temperature to 60°C for 30-60 minutes, and cool down to room temperature overnight. After TLC detects that there is no reactant, the reaction is complete. An appropriate amount of et...

Embodiment 2

[0034] Add 2-bromo-3-nitrotoluene (20.3kg), ethanol (203.0kg), and 5% palladium carbon (0.2kg) into the hydrogenation kettle. After the replacement is completed, control the pressure to 0.2-0.6MPa and the temperature to 45-55°C , hydrogenation reduction, sampling point plate detection, bromide disappears, hydrogenation is completed, cooled to room temperature, discharged, filtered, and desolvated under reduced pressure. A brown oil was obtained. Concentration under reduced pressure was carried out, and the temperature was controlled to be below 100° C. and evaporated to obtain 15.7 kg of pure product with a molar yield of 90%.

Embodiment 3

[0036] Add 2-bromo-3-aminotoluene (8.8kg), dioxane (26.2kg), and water (53.9kg) to reflux, add concentrated sulfuric acid (18.9kg) dropwise, and reflux for 1 to 2 hours. After reflux, cool down to 0-20°C and start adding sodium nitrite aqueous solution (3.3kg / 35.1kg) dropwise, and control the temperature between 0-20°C for about 1 hour. After dropping, stir at 0-20°C for 2 hours, and prepare potassium iodide aqueous solution (9.0 / 35.1 / kg). Concentrated sulfuric acid (18.9kg), after addition, was cooled to 0°C for use. Add the system dropwise to the reaction kettle with potassium iodide and concentrated sulfuric acid solution (control the temperature to 0-20°C, after about 1 hour, there will be more foam and more elemental iodine will be generated). After dropping, control the temperature at 0-20°C and stir for 2 hours, raise the temperature to 60°C for 2 hours, and cool down to room temperature for 2 hours (or overnight). The TLC raw material disappeared, and ethyl acetate w...

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Abstract

The invention discloses a novel method for preparing 2-bromo-3-iodotoluene, and belongs to the field of chemical synthesis. The method specifically comprises the following steps: a, reacting 2-amino-3-nitrotoluene serving as a raw material with a hydrobromic acid reagent under the action of nitrite and alkali metal bromide to prepare 2-bromo-3-nitrotoluene; b, taking 2-bromo-3-nitrotoluene as a raw material, and preparing 2-bromo-3-aminotoluene through a hydrogenation reduction reaction under the condition of a palladium catalyst; and c, taking 2-bromo-3-aminotoluene as a raw material, and reacting under the action of nitrite, concentrated acid and alkali metal iodide to prepare the 3-iodo-2-bromotoluene.

Description

technical field [0001] The invention relates to a novel method for preparing 3-iodo-2 bromotoluene, which belongs to the technical field of chemical synthesis. Background technique [0002] As we all know, 3-iodo-2-bromotoluene is an important starting material for the synthesis of drugs and is widely used. In the traditional preparation of 3-iodo-2-bromotoluene, iron powder is usually used for nitro reduction, so the post-reduction treatment is very troublesome, centrifugation is not easy, and a large amount of iron sludge will be generated, the amount of solid waste is relatively large, and there are potential safety hazards . Contents of the invention [0003] (1) Solved technical problems [0004] In order to solve the above problems, the present invention intends to use 2-amino-3-nitrotoluene as a raw material, which is a commonly used reagent in chemical research and can be purchased in large quantities on the market. The route designed by the present invention ad...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/093C07C25/02C07C209/36C07C211/52C07C201/12C07C205/12
CPCC07C17/093C07C209/365C07C201/12C07C205/12C07C211/52C07C25/02
Inventor 瞿鑫马良
Owner 河北唯达生物医药产业技术研究有限公司
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