The preparation method of 2-bromo-5-fluorobenzotrifluoride

Abstract

The invention discloses a method for preparing 2-bromine-5-fluoro-benzo-trifluoride, and belongs to the field of organic synthesis. The method comprises the following steps: firstly, mixing sulfuric acid with fluorobenzotrifluoride, and further adding bromated into the obtained mixture at 0-80 DEG C to react, thereby obtaining 2-bromine-5-fluorobenzotrifluoride. Through the adoption of the method, the yield can be greater than 90.0%, the purity is greater than 99.0%, the raw materials are easy to obtain, and the reaction condition is mild and easy to control.

Description

technical field

[0001] The invention relates to a compound preparation method, especially a compound synthesis method suitable for medicine and pesticide intermediates, and belongs to the field of organic synthesis. Background technique

[0002] 2-Bromo-5-fluorobenzotrifluoride has a wide range of uses, mainly used as pharmaceutical and pesticide intermediates. At present, there are several domestic patents on the preparation method of this compound, but there is no literature report on the synthesis of this product abroad. The domestically applied patent preparation methods mainly include: 1. Using m-fluorobenzotrifluoride as raw material, using a special bromination reagent 1,3-dibromo-2,4-imidazoledione to obtain 2-bromo-5- Fluorotrifluorotoluene. The advantage of this method is that the reaction yield is high, and the steps are simple. The disadvantage is that the bromination reagent is not easy to obtain, and the domestic supply is very small, and it is not a popular c...

Examples

Embodiment 1

[0023] Add 6.00kg of 70% sulfuric acid into a 10L glass reactor, pass through frozen brine, control the temperature below 30°C, add 0.66kg of m-fluorobenzotrifluoride under stirring, heat the mixture to keep the temperature at 45-50°C, divide Add 0.80kg powdered potassium bromate in 10 batches for about 4 hours. After the addition, continue to keep warm and stir for 2 hours. Take samples for analysis until the reaction is complete, quench, extract with 3L dichloromethane, wash with sodium sulfite, remove the solvent after alkali washing, and rectify The 158-162°C / 760mmHg fraction was collected to obtain a product with a weight of 0.92kg, a purity of 99.2%, and a yield of 93.9%.

Embodiment 2

[0025] Add 6.00kg of 70% sulfuric acid into a 10L glass reactor, pass through frozen brine, control the temperature below 30°C, add 0.66kg of m-fluorobenzotrifluoride under stirring, heat the mixture to keep the temperature at 45-50°C, divide Add 1.00kg powdered potassium bromate in 10 batches for about 4 hours. After the addition, continue to keep warm and stir for 2 hours. Take samples for analysis until the reaction is complete, quench, extract with 3L dichloromethane, wash with sodium sulfite, remove the solvent after alkali washing, and rectify The 158-162°C / 760mmHg fraction was collected to obtain a product with a weight of 0.91kg, a purity of 99.0%, and a yield of 92.7%.

Embodiment 3

[0027] Add 6.00kg of 70% sulfuric acid into a 10L glass reactor, pass through frozen brine (water bath, the same below), control the temperature below 30°C, add 0.66kg of m-fluorobenzotrifluoride under stirring, and heat the mixture to keep the temperature at 30~35℃, add 0.80kg powdered potassium bromate in 10 batches, about 4 hours, continue to keep warm and stir for 2 hours after adding, take samples and analyze until the reaction is completed, quench, extract with 3L dichloromethane, wash with sodium sulfite, wash with alkali After precipitating, rectification collects 158~162 ℃ / 760mmHg distillate, obtains product weight 0.90kg, purity 99.1%, yield 91.7%.

technical field

[0001] The invention relates to a compound preparation method, especially a compound synthesis method suitable for medicine and pesticide intermediates, and belongs to the field of organic synthesis. Background technique

[0002] 2-Bromo-5-fluorobenzotrifluoride has a wide range of uses, mainly used as pharmaceutical and pesticide intermediates. At present, there are several domestic patents on the preparation method of this compound, but there is no literature report on the synthesis of this product abroad. The domestically applied patent preparation methods mainly include: 1. Using m-fluorobenzotrifluoride as raw material, using a special bromination reagent 1,3-dibromo-2,4-imidazoledione to obtain 2-bromo-5- Fluorotrifluorotoluene. The advantage of this method is that the reaction yield is high, and the steps are simple. The disadvantage is that the bromination reagent is not easy to obtain, and the domestic supply is very small, and it is not a popular c...

Examples

Embodiment 1

[0023] Add 6.00kg of 70% sulfuric acid into a 10L glass reactor, pass through frozen brine, control the temperature below 30°C, add 0.66kg of m-fluorobenzotrifluoride under stirring, heat the mixture to keep the temperature at 45-50°C, divide Add 0.80kg powdered potassium bromate in 10 batches for about 4 hours. After the addition, continue to keep warm and stir for 2 hours. Take samples for analysis until the reaction is complete, quench, extract with 3L dichloromethane, wash with sodium sulfite, remove the solvent after alkali washing, and rectify The 158-162°C / 760mmHg fraction was collected to obtain a product with a weight of 0.92kg, a purity of 99.2%, and a yield of 93.9%.

Embodiment 2

[0025] Add 6.00kg of 70% sulfuric acid into a 10L glass reactor, pass through frozen brine, control the temperature below 30°C, add 0.66kg of m-fluorobenzotrifluoride under stirring, heat the mixture to keep the temperature at 45-50°C, divide Add 1.00kg powdered potassium bromate in 10 batches for about 4 hours. After the addition, continue to keep warm and stir for 2 hours. Take samples for analysis until the reaction is complete, quench, extract with 3L dichloromethane, wash with sodium sulfite, remove the solvent after alkali washing, and rectify The 158-162°C / 760mmHg fraction was collected to obtain a product with a weight of 0.91kg, a purity of 99.0%, and a yield of 92.7%.

Embodiment 3

[0027] Add 6.00kg of 70% sulfuric acid into a 10L glass reactor, pass through frozen brine (water bath, the same below), control the temperature below 30°C, add 0.66kg of m-fluorobenzotrifluoride under stirring, and heat the mixture to keep the temperature at 30~35℃, add 0.80kg powdered potassium bromate in 10 batches, about 4 hours, continue to keep warm and stir for 2 hours after adding, take samples and analyze until the reaction is completed, quench, extract with 3L dichloromethane, wash with sodium sulfite, wash with alkali After precipitating, rectification collects 158~162 ℃ / 760mmHg distillate, obtains product weight 0.90kg, purity 99.1%, yield 91.7%.

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