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Synthesis process of 2-bromo-4-iodo-3-methylpyridine

A technology for the synthesis of picoline, which is applied in the field of synthesis of 2-bromo-4-iodo-3-picoline, can solve the problems of no literature reports in the synthesis, and achieve good product quality and cheap and easy-to-obtain raw materials , the effect of high yield

Inactive Publication Date: 2021-01-12
乐威医药(天津)有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] There is no literature report on the synthesis of 2-bromo-4-iodo-3-methylpyridine at home and abroad

Method used

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  • Synthesis process of 2-bromo-4-iodo-3-methylpyridine
  • Synthesis process of 2-bromo-4-iodo-3-methylpyridine
  • Synthesis process of 2-bromo-4-iodo-3-methylpyridine

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Experimental program
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Effect test

Embodiment 11

[0031] Dissolve 2,2,6,6-tetramethylpiperidine (10.9g, 69mmol, 1.1eq) in tetrahydrofuran (40mL), replace the system with nitrogen three times, cool to below -20°C, and add n- Butyllithium (32mL, 69mmol, 1.1eq), there is a large amount of exothermic and degassing phenomenon during the dropping process, and the temperature control during the process does not exceed -20°C. After the dropwise addition, the temperature is controlled below -70°C for 1 hour. Bromopyridine (10.0g, 63mmol, 1.0eq), after the addition is complete, react at a temperature of -70~-60°C for 2h, then add 1M tetrahydrofuran solution of anhydrous zinc chloride (69mL, 69mmol, 1.1eq), continue to Reaction 1h. A mixed solution of iodine (24.0g, 95mmol, 1.5eq) and tetrahydrofuran (50mL) was added dropwise, and the reaction was continued for 0.5h. Monitoring shows that there are few remaining raw materials, stop the reaction, naturally rise to room temperature, add 100mL of saturated aqueous ammonium chloride soluti...

Embodiment 12

[0033] Dissolve 2,2,6,6-tetramethylpiperidine (49.2g, 348mmol, 1.1eq) in tetrahydrofuran (250mL), replace the system with nitrogen three times, cool to below -50°C, and add n- Butyllithium (158mL, 348mmol, 1.1eq), during the dropwise addition process, there is a large amount of exothermic and gas-releasing phenomena, the process temperature control does not exceed 0°C, and the temperature is controlled below 0°C for 0.5 hours, the system is cooled to below -70°C again, drop Add 2-bromopyridine (50.0g, 316mmol, 1.0eq), after the addition is complete, control the temperature at -70~-60°C for 2h, then add anhydrous magnesium chloride (33.1g, 348mmol, 1.1eq), continue the reaction for 0.5 h, generating a brown-green solid suspension. A mixed solution of iodine (80.3g, 316mmol, 1.0eq) and tetrahydrofuran (200mL, 4.0vol) was added dropwise, and the reaction was continued for 0.5h, turning into a red-black solution. Monitoring showed that there were few remaining raw materials, and ...

Embodiment 21

[0036] Dissolve 2-bromo-3-iodopyridine (10g, 35mmol, 1.0eq) in THF (100mL, 10vol), stir until completely dissolved, warm to -70°C, add dropwise n-BuLi n-hexane solution (14mL , 35mmol, 1.0eq), the dropwise addition was completed, stirred for 10min, then added dropwise methyl iodide (15g, 105mmol, 3.0eq), continued to stir for 30min, TLC showed that no raw material remained, raised the temperature to 0°C, and slowly added 50mL of saturated sulfurous acid dropwise Sodium hydrogen aqueous solution quenched the reaction, and the reaction system was naturally raised to room temperature, added ethyl acetate (100mL × 2) for extraction, combined organic phases, washed with 25% sodium chloride aqueous solution (100mL), and allowed to stand for liquid separation. The phase was concentrated under reduced pressure until no liquid emerged, and weighed to obtain 1.8 g of liquid, with a yield of 30%.

[0037]Dissolve 2-bromo-3-methylpyridine (10g, 58mmol, 1.0eq) in a mixture of tetrahydrofur...

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Abstract

The invention provides a synthesis process of 2-bromo-4-iodo-3-methylpyridine. The process is characterized by comprising the following steps: S1, carrying out halogenation reaction on 2-bromopyridineserving as a raw material to generate 2-bromo-3-iodopyridine; and S2, carrying out a halogen dance reaction on the raw material 2-bromo-3-iodopyridine to generate 2-bromo-4-iodo-3-methylpyridine. According to the invention, cheap and easily available 2-bromopyridine is used as a raw material to synthesize the raw material 2-bromo-3-iodopyridine for the halogen dance reaction, the synthesis process is also researched and optimized, a step-by-step synthesis method is adopted and the connection sequence of functional groups is changed to break through the route, the overall yield after optimization is low, and then a one-pot synthesis method is researched according to a halogen dance reaction mechanism. The process route has the characteristics of high yield, good product quality, cheap andeasily available initial raw materials and the like.

Description

technical field [0001] The invention relates to a synthesis process of 2-bromo-4-iodo-3-picoline. Background technique [0002] Halogenated picolines are important fine chemical intermediates and are widely used in the fields of medicine and pesticides. Halogenated pyridines containing bromine and iodine are widely used in the fields of pesticides, medicines, and functional materials. [0003] The halide reaction mainly refers to the reaction in alkali (NaNH 2 , LDA, t-BuOK, Grignard reagent and BuLi), the reaction in which the halogen substituents in halogenated aromatic compounds (including aromatic rings and aromatic heterocyclic rings) move to new substitution positions. This reaction was first reported by Vaitiekunas research group in 1951. It can be used in aromatic rings or aromatic heterocyclic rings to achieve effective functionalization at positions that are difficult to access by other methods, and has important synthetic application value. [0004] There is no...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 李巍
Owner 乐威医药(天津)有限公司
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