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Synthesis method of 2,3-dichloro-5-methylpyridine

A technology of picoline and benzyl, which is applied in the field of synthesis of 2,3-dichloro-5-picoline, can solve the problems of high cost, low yield, and high toxicity of raw materials, and achieve low cost and high yield High and low toxicity of raw materials

Active Publication Date: 2014-01-15
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

These methods also have the defects of low yield, high toxicity of raw materials and high cost. It is necessary to develop new methods that are more suitable for industrial applications

Method used

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  • Synthesis method of 2,3-dichloro-5-methylpyridine

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Experimental program
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Effect test

Embodiment 1

[0018] Embodiment 1: the preparation of N-benzyl-N-propenyl-alpha-chloroacetamide

[0019] Add 73.5g (0.50mol) of N-propylidenebenzylamine, 100mL of ethyl acetate and 55.6g (0.55mol) of triethylamine into a 500mL four-neck flask, stir and cool down to 0°C, and dropwise add 59.3g of chloroacetyl chloride ( 0.525mol), the dropwise addition was completed within 1-2 hours, then the temperature was raised to 30°C and the reaction was stirred for 1 hour, and the reaction was complete as detected by GC-MS. The reaction liquid was washed successively with 100 mL of water, 50 mL of 10% hydrochloric acid, 50 mL of 10% sodium hydroxide solution, and 50 mL of saturated brine, and then distilled off the solvent under reduced pressure to obtain 109.6 g of viscous liquid, N-benzyl-N-propenyl-α - Chloroacetamide content 96.1%, yield 94.3%.

Embodiment 2

[0020] Embodiment 2: Preparation of N-benzyl-N-propenyl-α-chloroacetamide

[0021] Add 73.5g (0.50mol) of N-propylidene benzylamine, 100mL tetrahydrofuran and 47.4g (0.60mol) of pyridine into a 500mL four-neck flask, stir and cool down to 0°C, add 62.2g (0.55mol) of chloroacetyl chloride dropwise, After 1-2 hours, the dropwise addition was completed, then the temperature was raised to 10°C and the reaction was stirred for 3 hours, and the reaction was detected by GC-MS to be complete. The reaction liquid was washed successively with 100 mL of water, 50 mL of 10% hydrochloric acid, 50 mL of 10% sodium hydroxide solution, and 50 mL of saturated brine, and then distilled off the solvent under reduced pressure to obtain 111.3 g of a viscous liquid, N-benzyl-N-propenyl-α - Chloroacetamide content 95.9%, yield 95.5%.

Embodiment 3

[0022] Embodiment 3: Preparation of 2,3-dichloro-5-picoline

[0023] Add 9.8g (0.058mol) of dimethylchloromethylene ammonium chloride and 100mL of 1,2-dichloroethane into a 250mL three-necked flask, stir and cool down to 10°C, and the N-benzyl- Dissolve 11.1g (0.048mol) of N-propenyl-α-chloroacetamide in 50mL of 1,2-dichloroethane, slowly add it dropwise into the reaction flask, control the temperature within 50°C, raise the temperature to 50°C after the addition, The reaction was incubated for 8 hours, and the reaction was detected by GC-MS to be complete. The reaction solution was washed successively with 100 mL of water, 50 mL of 10% sodium hydroxide and 50 mL of water, and the solvent was distilled off under reduced pressure to obtain an oily liquid, which was then recrystallized by adding 30 mL of n-hexane to obtain 6.6 g of colorless crystals, 2,3-dichloro-5 -The picoline content is 99%, and the yield is 84.1%. M.p.41-43℃, GC-MS (m / z): 161 (100), 126, 98, 90, 73, 63; ...

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Abstract

The invention provides a synthesis method of 2,3-dichloro-5-methylpyridine. The method comprises following steps: taking N-propylidene benzylamine as the primary raw material, carrying out acylation reactions between the N-propylidene benzylamine and chloroacetyl chloride in the action of an acid binding agent at the temperature of minus 10 DEG C to 60 DEG C so as to obtain N-benzyl-N-propenyl-alpha-chloroacetamide, and then carrying out cyclization reactions between the N-benzyl-N-propenyl-alpha-chloroacetamide and (dichloromethylene)dimethylammonium chloride at the temperature of 20 DEG C to 120 DEG C so as to obtain 2,3-dichloro-5-methylpyridine. Compared to the conventional methods, the synthesis method has the advantages of little raw material toxicity, high yield, low cost, mild reaction conditions, and little waste water, waste gas, and waste solid, and has an industrial application value.

Description

(1) Technical field [0001] The invention relates to a synthesis method of 2,3-dichloro-5-picoline. (2) Background technology [0002] 2,3-Dichloro-5-methylpyridine is a key intermediate for the synthesis of high-efficiency and safe pesticides such as haloxyfop, diflurane, and fluazinam. Setliff et al. (J.Chem.Eng.Data, 1976,21 (2), 246) reported the synthesis of 2,3-dichloro -5-picoline method. EP46735, US4435573 and US4469896 disclose the method of using 2,2-dichloropropanal to add acrylonitrile and ring closure to obtain 2,3-dichloro-5-methylpyridine. EP137415 discloses a method for synthesizing 2,3-dichloro-5-methylpyridine using dichloroacetonitrile and 2-methacrolein as raw materials. These methods also have the defects of low yield, high toxicity of raw materials and high cost, so it is necessary to develop new methods that are more suitable for industrial applications. (3) Contents of the invention [0003] The object of the present invention is to provide a met...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 杜晓华郑旺赵琦君徐振元
Owner ZHEJIANG UNIV OF TECH
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