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A kind of preparation method of 2,4-dichloro-5-methoxypyrimidine

A technology of methoxypyrimidine and mercapto, which is applied in the field of preparation of 2,4-dichloro-5-methoxypyrimidine, can solve the problems of low yield and large amount of chlorinating agent, and achieve high yield and chlorine The effect of low dosage of agent and novel synthetic route

Active Publication Date: 2019-03-15
CHAMBROAD CHEM IND RES INST CO LTD
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

Chinese Invention Patent Publication No. CN101486684A describes a synthetic method of 2,4-dichloro-5-methoxypyrimidine, using ethyl formate and methyl methoxyacetate as starting materials, undergoing ester condensation and cyclization , chlorination to obtain the target product, the amount of chlorination agent is large, the total yield is between 57%-67%, and the yield is on the low side

Method used

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  • A kind of preparation method of 2,4-dichloro-5-methoxypyrimidine
  • A kind of preparation method of 2,4-dichloro-5-methoxypyrimidine

Examples

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Effect test

Embodiment 1

[0020] A) To prepare 2-mercapto-4-hydroxy-5-methoxypyrimidine, add 185 g (2.5 mol) of ethyl formate into the device, add 91.8 g (1.7 mol) of sodium methoxide solid under stirring, and add dropwise to the system below 20°C 104g (1mol) of methyl methoxyacetate, the dropwise addition was completed and the temperature was kept at 20°C for 300min to obtain compound I; then, 340ml of methanol was added to compound I and heated to 65°C and stirred until compound I was uniformly dispersed, and 114g (1.5mol) of thiourea was added. ), reflux for 260min, concentrate to 1 / 4 volume, add 330ml of water to dissolve, cool to 10°C, adjust the pH value to 2 with hydrochloric acid, filter, wash the filter cake twice with 100ml of water, dry at 100°C for 8h to obtain 145.3g of compound Ⅱ, the yield was 92%, and the HPLC purity was 99.7%;

[0021] B) To prepare 2,4-dichloro-5-methoxypyrimidine, in a 500ml four-necked flask equipped with a thermometer, reflux condenser, ventilation device and mecha...

Embodiment 2

[0023] A) Prepare 2-mercapto-4-hydroxyl-5-methoxypyrimidine, using the same method as in Example 1 to obtain compound I; then add 340ml methanol to compound I and heat to 65°C and stir until compound I is uniformly dispersed, add sulfur Urea 152g (2mol), reflux for 240min, concentrate to 1 / 4 volume, add 330ml water to dissolve, cool to 10°C, adjust pH value to 3 with acetic acid, filter, wash filter cake twice with 100ml water, dry at 100°C for 8h 150.1 g of compound II was obtained with a yield of 95% and a purity of 99.6% by HPLC;

[0024] B) To prepare 2,4-dichloro-5-methoxypyrimidine, in a 500ml four-necked flask equipped with a thermometer, reflux condenser, ventilation device and mechanical stirring, add 250ml dichloropyrimidine to compound II 79g (0.5mol) Ethane was passed through with chlorine gas at a rate of 3 g / min, and reacted at 20° C. for 400 min to obtain compound III. Then, 101 g (0.5 mol) of triethylamine and 84.4 g (0.55 mol) of phosphorus oxychloride were s...

Embodiment 3

[0026] A) Prepare 2-mercapto-4-hydroxyl-5-methoxypyrimidine, using the same method as in Example 1 to obtain compound I; then add 340ml methanol to compound I and heat to 65°C and stir until compound I is uniformly dispersed, add sulfur Urea 152g (3mol), reflux for 180min, concentrate to 1 / 4 volume, add 330ml water to dissolve, cool to 10°C, adjust pH value to 5 with sulfuric acid, filter, wash filter cake twice with 100ml water, dry at 100°C for 8h 144.25 g of compound II was obtained with a yield of 91.3% and a purity of 99.2% by HPLC;

[0027] B) To prepare 2,4-dichloro-5-methoxypyrimidine, in a 500ml four-necked flask equipped with a thermometer, reflux condenser, ventilation device and mechanical stirring, add 250ml dichloropyrimidine to compound II 79g (0.5mol) Ethane was passed through with chlorine gas at a rate of 1 g / min, and reacted at 30° C. for 420 min to obtain compound III. Then put 79g (1mol) of pyridine and 115.15g (0.75mol) of phosphorus oxychloride into the...

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Abstract

The invention relates to a preparation method of 2,4-dichloro-5-methoxypyrimidine, and belongs to the technical field of the preparation of intermediates of pesticides. According to the method, first, ethyl formate and methyl methoxyacetate are used as raw materials, and 2-thiol-4-hydroxyl-5-methoxypyrimidine is made through condensation and cyclization; afterwards, chlorination is carried out by using chlorine and phosphorus oxychloride successively, so as to obtain the 2,4-dichloro-5-methoxypyrimidine. All raw materials for the preparation method of the 2,4-dichloro-5-methoxypyrimidine are easily obtained; a synthetic route is novel; the yield of a ring formation step is high; the use level of a chlorinating agent is low; the preparation method of the 2,4-dichloro-5-methoxypyrimidine is suitable for industrialized production.

Description

technical field [0001] The invention belongs to the technical field of preparation of pesticide intermediates, in particular to a preparation method of 2,4-dichloro-5-methoxypyrimidine. technical background [0002] 2,4-Dichloro-5-methoxypyrimidine is an important intermediate for the synthesis of a new type of high-efficiency and low-toxicity herbicide 2-amino-5,8-dimethoxy[1,2,4]triazole An important raw material for [1,5-c]pyrimidine. Chinese Invention Patent Publication No. CN101486684A describes a synthetic method of 2,4-dichloro-5-methoxypyrimidine, using ethyl formate and methyl methoxyacetate as starting materials, undergoing ester condensation and cyclization , Chlorination to obtain the target product, the amount of chlorination agent used is large, the total yield is between 57%-67%, and the yield is on the low side. From the perspective of cost reduction, the applicant explored a method with easy-to-obtain raw materials, low cost, simple synthesis and meeting t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D239/34
CPCC07D239/34
Inventor 于龙姚刚常金磊刘鹏樊其燕刘克锋
Owner CHAMBROAD CHEM IND RES INST CO LTD
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