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Preparing method of 3,4,6-trichloropyridine-2-formic acid and ester thereof

A technology of triclopyridine and picolinic acid, which is applied in the direction of organic chemistry, can solve the problems of low yield, long synthesis line, high production cost, etc., and achieve the effects of high yield, low production cost and poor safety

Active Publication Date: 2017-01-04
LIER CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a 3,4 , the preparation method of 6-trichloropyridine-2-carboxylic acid and its ester

Method used

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  • Preparing method of 3,4,6-trichloropyridine-2-formic acid and ester thereof
  • Preparing method of 3,4,6-trichloropyridine-2-formic acid and ester thereof

Examples

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Effect test

Embodiment 1

[0024] Example 1 Preparation of 3,4,6-trichloropyridine-2-carboxylic acid

[0025] Add 240ml of water and 90ml of concentrated hydrochloric acid to a 1L reaction flask, and add 108.68g (0.525mol) of 3,6-dichloro-4amino-2-pyridinecarboxylic acid into the reaction flask under stirring, then slowly Add dropwise sodium nitrite solution (this sodium nitrite solution contains 51g (0.6mol) sodium nitrite and 90ml water), after dropwise addition, keep stirring until 3,6-dichloro-4 amino-2-pyridinecarboxylic acid disappears, A reaction solution was obtained. Slowly heat the reaction solution to 60°C to 100°C, preferably 75°C to 80°C, keep it warm for 3 hours, then cool down to room temperature, then extract three times with ethyl acetate, the amount of ethyl acetate each time is 120mL, and combine the organic phases. The organic phase was washed with water, concentrated, and then recrystallized to obtain 3,4,6-trichloropyridine-2-carboxylic acid with a content of 98%.

[0026] Under ...

Embodiment 2

[0029] Example 2 Preparation of 3,4,6-trichloropyridine-2-carboxylate

[0030] Add 10g (0.0444mol) of 3,4,6-trichloropyridine-2-carboxylic acid to a 100mL reaction flask, then add 20g of methanol and 1g of concentrated sulfuric acid, and heat up to reflux for 16 hours. After the reaction is complete, distill out the methanol under reduced pressure, and then Then collect the fraction at 155-160°C under the condition of -0.098MPa. Add methanol three times the mass of the fraction to the fraction, heat to reflux, cool to 0°C, and filter under reduced pressure to obtain the mother liquor. After the mother liquor was spin-dried, it was beaten with methanol, cooled and filtered with suction to obtain 9.5 g of methyl 3,4,6-trichloropyridine-2-carboxylate as a white solid.

[0031] It is determined that the mp (melting point, referred to as: melting point) of the prepared white solid is 60-63°C, 1 HNMR (400MHz, CDCl3) δ 7.58 (s, 1H), 4.01 (s, 3H) ppm.

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Abstract

The invention discloses a preparing method of 3,4,6-trichloropyridine-2-formic acid and ester thereof, and aims to solve the problems that an existing preparing method of 3,4,6-trichloropyridine-2-formic acid and ester thereof is low in yield and high in production cost, and the synthesis path is long. The preparing method of 3,4,6-trichloropyridine-2-formic acid includes the following steps that 3,6-dichloro-4-amino-2-picolinic acid, hydrochloric acid and sodium nitrite are mixed, and after mixing is completed, reaction liquid is heated to obtain 3,4,6-trichloropyridine-2-formic acid. The preparing method includes simple operation steps and a short process, the yield is up to 74% or more, and the purity reaches 98%, and the preparing method is remarkably better than the prior art and has good application prospects. Meanwhile, the synthesis path is short, raw material cost is low, the production cost of 3,4,6-trichloropyridine-2-formic acid and ester thereof can be effectively reduced, the requirement of large-scale industrial production is met, and the preparing method is of great significance in promoting application and development of 3,4,6-trichloropyridine-2-formic acid and ester thereof.

Description

technical field [0001] The present invention relates to the field of chemical industry, especially the field of synthesis, specifically a preparation method of 3,4,6-trichloropyridine-2-carboxylic acid and its esters, that is, 3,4,6-trichloropyridine-2-carboxylic acid The preparation method and the preparation method of 3,4,6-trichloropyridine-2-carboxylate further include the preparation method of 3,4,6-trichloropyridine-2-carboxylic acid methyl ester. Background technique [0002] Chloropyridine carboxylic acid derivatives are an important class of chemical intermediates, widely used in pesticides, pharmaceutical synthesis and other fields. Among them, 3,4,6-trichloropyridine-2-carboxylic acid and its corresponding esters are important compounds among polychlorinated pyridinecarboxylic acid derivatives. [0003] 3,4,6-trichloropyridine-2-carboxylic acid and its corresponding esters are useful fine chemical intermediates, and their use in the synthesis of herbicides has be...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/803C07D213/79
CPCC07D213/79C07D213/803
Inventor 晏三军任杰
Owner LIER CHEM CO LTD
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