Synthetic method of 2-chloro-5-chloromethyl pyridine

Abstract

The invention discloses a synthetic method of 2-chloro-5-chloromethyl pyridine. The synthetic method comprising the following steps: adding an organic solvent, an acid buffering agent solution and an initiator into 3-methylpyridine; adjusting the pH value of the solution in a range of 4-5; letting nitrogen in; elevating temperature to 80-100 DEG C while stirring; stopping letting nitrogen in, letting chlorine in and continuing elevating temperature for a reaction; stopping heating, shutting a chlorine injection vavle off, letting nitrogen in and bubbling to drive the chlorine off; desolventizing a reaction solution through underpressure distillation to obtain brown-red oily liquid; and purifying the brown-red oily liquid to obtain a finished product. According to the invention, a liquid phase chlorination method is adopted; raw materials are subjected to a reaction in liquid; meanwhile an acid buffering agent solution is added to adjust a pH value in a range of 4-5; and by-products are decreased, so that the yield of a target product can reach to about 90%.

Description

technical field

[0001] The invention relates to a synthesis method of 2-chloro-5-chloromethylpyridine, which belongs to the field of organic chemical synthesis. Background technique

[0002] 2-Chloro-5-chloromethylpyridine (abbreviated as CCMP) is an important intermediate of neonicotinoid pesticides such as imidacloprid, acetamiprid and piperacrid, and can be used in the preparation of pharmaceuticals, agricultural chemicals and biological agents, etc. Especially the important intermediates for the synthesis of high-efficiency new pesticides haloxyfop, imidacloprid, and future new pesticides containing chloropyridines, new pesticides containing chloropyridines synthesized from 2-chloro-5-trichloromethylpyridine, At present, it is being vigorously researched and developed at home and abroad.

[0003] At present, there are three main routes for synthesizing 2-chloro-5-chloromethylpyridine by ring method, which are benzylamine method, cyclopentadiene method and morpholine met...

Examples

Embodiment 1

[0018] Add 10g of 3-picoline, 30mL of nitrobenzene and 45ml of buffer solution into a four-neck flask, adjust the pH value of the solution to about 4 with dilute hydrochloric acid, and add 0.2g of phosphorus trichloride at the same time. Introduce nitrogen, electromagnetically stir, heat up to 80°C, stop nitrogen flow and switch to chlorine gas, continue to heat up to 120°C, under constant temperature, chlorine gas bubbling reaction for 12h, stop heating, close the chlorine gas injection valve, pass in nitrogen gas, bubbling Soak chlorine for 1h. After the reaction solution was distilled off under reduced pressure, a brown-red oily liquid was obtained. The product was purified by high vacuum fractional distillation, and the distillate was collected. After extraction with chloroform, the extracts were combined, and after desolvation under reduced pressure, 18.9 g of a light yellow oily liquid was obtained, and the yield of the product 2-chloro-5-trichloromethylpyridine was 89....

Embodiment 2

[0020] Add 10g of 3-picoline, 25mL of nitrobenzene and 25ml of buffer solution into a four-neck flask, adjust the pH value of the solution to about 4.5 with dilute hydrochloric acid, and add 0.3g of phosphorus trichloride at the same time. Introduce nitrogen, electromagnetically stir, heat up to 100°C, stop nitrogen flow and switch to chlorine gas, continue to heat up to 140°C, under constant temperature, chlorine gas bubbling reaction for 16h, stop heating, close the chlorine gas sampling valve, pass in nitrogen gas, bubbling Soak chlorine for 1h. After the reaction solution was distilled off under reduced pressure, a brown-red oily liquid was obtained. The product was purified by high vacuum fractional distillation, and the distillate was collected. After extraction with chloroform, the extracts were combined, and after desolvation under reduced pressure, 19.4 g of a light yellow oily liquid was obtained, and the yield of the product 2-chloro-5-trichloromethylpyridine was 9...

Embodiment 3

[0021] Add 10g of 3-picoline, 45mL of nitrobenzene and 90ml of buffer solution into a four-neck flask, adjust the pH value of the solution to about 5 with dilute hydrochloric acid, and add 0.5g of phosphorus trichloride at the same time. Introduce nitrogen, electromagnetically stir, heat up to 90°C, stop nitrogen flow and switch to chlorine gas, continue to heat up to 160°C, under constant temperature, chlorine gas bubbling reaction for 20h, stop heating, close the chlorine gas injection valve, pass in nitrogen gas, bubbling Soak chlorine for 1h. After the reaction solution was distilled off under reduced pressure, a brown-red oily liquid was obtained. The product was purified by high vacuum fractional distillation, and the distillate was collected. After extraction with chloroform, the extracts were combined, and after desolvation under reduced pressure, 19.1 g of a light yellow oily liquid was obtained, and the yield of the product 2-chloro-5-trichloromethylpyridine was 90....

technical field

[0001] The invention relates to a synthesis method of 2-chloro-5-chloromethylpyridine, which belongs to the field of organic chemical synthesis. Background technique

[0002] 2-Chloro-5-chloromethylpyridine (abbreviated as CCMP) is an important intermediate of neonicotinoid pesticides such as imidacloprid, acetamiprid and piperacrid, and can be used in the preparation of pharmaceuticals, agricultural chemicals and biological agents, etc. Especially the important intermediates for the synthesis of high-efficiency new pesticides haloxyfop, imidacloprid, and future new pesticides containing chloropyridines, new pesticides containing chloropyridines synthesized from 2-chloro-5-trichloromethylpyridine, At present, it is being vigorously researched and developed at home and abroad.

[0003] At present, there are three main routes for synthesizing 2-chloro-5-chloromethylpyridine by ring method, which are benzylamine method, cyclopentadiene method and morpholine met...

Examples

Embodiment 1

[0018] Add 10g of 3-picoline, 30mL of nitrobenzene and 45ml of buffer solution into a four-neck flask, adjust the pH value of the solution to about 4 with dilute hydrochloric acid, and add 0.2g of phosphorus trichloride at the same time. Introduce nitrogen, electromagnetically stir, heat up to 80°C, stop nitrogen flow and switch to chlorine gas, continue to heat up to 120°C, under constant temperature, chlorine gas bubbling reaction for 12h, stop heating, close the chlorine gas injection valve, pass in nitrogen gas, bubbling Soak chlorine for 1h. After the reaction solution was distilled off under reduced pressure, a brown-red oily liquid was obtained. The product was purified by high vacuum fractional distillation, and the distillate was collected. After extraction with chloroform, the extracts were combined, and after desolvation under reduced pressure, 18.9 g of a light yellow oily liquid was obtained, and the yield of the product 2-chloro-5-trichloromethylpyridine was 89....

Embodiment 2

[0020] Add 10g of 3-picoline, 25mL of nitrobenzene and 25ml of buffer solution into a four-neck flask, adjust the pH value of the solution to about 4.5 with dilute hydrochloric acid, and add 0.3g of phosphorus trichloride at the same time. Introduce nitrogen, electromagnetically stir, heat up to 100°C, stop nitrogen flow and switch to chlorine gas, continue to heat up to 140°C, under constant temperature, chlorine gas bubbling reaction for 16h, stop heating, close the chlorine gas sampling valve, pass in nitrogen gas, bubbling Soak chlorine for 1h. After the reaction solution was distilled off under reduced pressure, a brown-red oily liquid was obtained. The product was purified by high vacuum fractional distillation, and the distillate was collected. After extraction with chloroform, the extracts were combined, and after desolvation under reduced pressure, 19.4 g of a light yellow oily liquid was obtained, and the yield of the product 2-chloro-5-trichloromethylpyridine was 9...

Embodiment 3

[0021] Add 10g of 3-picoline, 45mL of nitrobenzene and 90ml of buffer solution into a four-neck flask, adjust the pH value of the solution to about 5 with dilute hydrochloric acid, and add 0.5g of phosphorus trichloride at the same time. Introduce nitrogen, electromagnetically stir, heat up to 90°C, stop nitrogen flow and switch to chlorine gas, continue to heat up to 160°C, under constant temperature, chlorine gas bubbling reaction for 20h, stop heating, close the chlorine gas injection valve, pass in nitrogen gas, bubbling Soak chlorine for 1h. After the reaction solution was distilled off under reduced pressure, a brown-red oily liquid was obtained. The product was purified by high vacuum fractional distillation, and the distillate was collected. After extraction with chloroform, the extracts were combined, and after desolvation under reduced pressure, 19.1 g of a light yellow oily liquid was obtained, and the yield of the product 2-chloro-5-trichloromethylpyridine was 90....