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Method for preparing 5-methoxy-4,6-dihydroxy pyrimidine disodium

A technology of dihydroxypyrimidine disodium and methoxymethyl ethyl malonate, which is applied in the field of preparation of chemical intermediates, can solve the problems of unsuitability for industrial production, low total product yield, long operation time, etc., and achieve Reduce the pretreatment process, improve the yield and quality, and reduce the effect of waste solvents

Active Publication Date: 2014-06-18
CHANGSHU JINSHEN MEDICAL PROD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The preparation process of the existing 5-methoxy-4,6-dichloropyrimidine generally includes Kjeldahl reaction, ring closure reaction, chlorination reaction, etc., the existing known 5-methoxy-4,6-dichloropyrimidine The preparation method of chloropyrimidine has following some defects: one, take 2-methoxyl-malonic acid dimethyl ester as starting raw material, form mercaptopyrimidine ring through condensation with thiourea, use Raney nickel demercapto group, obtain 4, 6-dihydroxy-5-methoxypyrimidine has high solubility in water, and it is difficult to extract from water, resulting in low total yield of product
However, due to the high price of formamidine salt, this route is not suitable for industrial production
3. The existing preparation technology of 5-methoxy-4,6-dichloropyrimidine is due to the use of a large amount of solvent and the long operation time in the preparation process, which leads to the loss of energy consumption and the yield of the final product. There are certain deficiencies in

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] A preparation method of 5-methoxy-4,6-dihydroxypyrimidine disodium, comprising the steps of:

[0015] 1) Kjeldahl reaction: put 120kg of solid sodium ethoxide into the reactor, then put in 175kg of methyl methoxyacetate and 200kg of diethyl oxalate, react for 1 hour, the temperature is controlled at 20°C, and 100kg of trichlorethylene is added after the reaction is completed. Stir and dilute, add 200kg of water, 100kg of 30% hydrochloric acid, adjust the pH value to 0.5, separate the trichlorethylene, extract the water layer with trichlorethylene for 4 times, recover the trichlorethylene solvent, and finally control the internal temperature to 90°C. Inner temperature 150°C, under vacuum state, decarbonylation for 3 hours, then vacuum distillation, collection vacuum degree ≥ -0.095MPa, inner temperature ≤ 250°C, to obtain 180kg methyl ethyl methoxymalonate;

[0016] 2) Ring closure reaction: first put 800kg of sodium methoxide into the reaction pot, add 0.5kg of silica-a...

Embodiment 2

[0018] A preparation method of 5-methoxy-4,6-dihydroxypyrimidine disodium, comprising the steps of:

[0019] 1) Kjeldahl reaction: put 220kg of solid sodium ethoxide into the reactor, then put in 175kg of methyl methoxyacetate and 320kg of diethyl oxalate, react for 5 hours, the temperature is controlled at 80°C, and 300kg of trichlorethylene is added after the reaction is completed. Stir and dilute, add 600kg of water, 400kg of 30% hydrochloric acid, adjust the pH value to 3.0, separate the trichlorethylene, extract the water layer with trichlorethylene for 8 times, recover the trichlorethylene solvent, and finally control the internal temperature to 130°C. Inner temperature 200°C, under vacuum state, decarbonylation for 8 hours, then vacuum distillation, collection vacuum degree ≥ -0.095MPa, inner temperature ≤ 250°C, to get 260kg methyl ethyl methoxymalonate;

[0020] 2) Ring closure reaction: first put 1400kg of sodium methoxide into the reaction pot, add 2.0kg of silica-a...

Embodiment 3

[0022] A preparation method of 5-methoxy-4,6-dihydroxypyrimidine disodium, comprising the steps of:

[0023] 1) Kjeldahl reaction: put 180kg solid sodium ethoxide into the reactor, then put 175kg methyl methoxyacetate and 260kg diethyl oxalate, react for 3 hours, control the temperature at 60°C, add 190kg trichlorethylene after the reaction, Stir and dilute, add 400kg of water, 200kg of 30% hydrochloric acid, adjust the pH value to 2.0, separate the trichlorethylene, extract the water layer with trichlorethylene for 6 times, recover the trichlorethylene solvent, and finally control the internal temperature to 100°C. Inner temperature 170°C, under vacuum state, decarbonylation for 5 hours, then vacuum distillation, collection vacuum degree ≥ -0.095MPa, inner temperature ≤ 250°C, to get 200kg methyl ethyl methoxymalonate;

[0024] 2) Ring closure reaction: first put 1000kg of sodium methoxide into the reaction pot, add 1.5kg of silica-alumina catalyst, stir and heat to 50°C, add...

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PUM

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Abstract

The invention discloses a method for preparing 5-methoxy-4,6-dihydroxy pyrimidine disodium. The method comprises the following steps: 1) performing Clancy reaction, namely, feeding solid sodium ethoxide into a reaction kettle, further feeding methoxyacetic acid methyl acetate and diethyl oxalate for reaction, after the reaction, adding trichloro ethylene, stirring and diluting, adding water, 30% hydrochloric acid, adjusting the pH value, separating trichloro ethylene, extracting a water layer by using trichloro ethylene, recycling a trichloro ethylene solvent, decarbonizing, and then performing reduced pressure distillation to obtain methoxy-malonic acid methyl ethyl ester; and 2) performing cyclization reaction, namely, firstly, feeding sodium methylate into a reaction pot, adding a silicon dioxide-aluminum oxide catalyst, stirring and heating, adding formamide and methoxy-malonic acid methyl ethyl ester, after that, keeping the temperature to react, after keeping the temperature, recycling methanol till no liquid is discharged, subsequently adding water, cooling, discharging, and rotating a damp product to dry under reduced pressure so as to obtain the 5-methoxy-4,6-dihydroxy pyrimidine disodium. The method disclosed by the invention is high in yield, can greatly reduce energy consumption, and is applicable to industrial production.

Description

technical field [0001] The invention belongs to the technical field of preparation of chemical intermediates, and in particular relates to a preparation method of disodium 5-methoxy-4,6-dihydroxypyrimidine. Background technique [0002] 5-Methoxy-4,6-dichloropyrimidine is an important organic intermediate, which is widely used in the field of pesticides and is one of the important intermediates for the synthesis of salicylic acid pyrimidine herbicides. [0003] The preparation process of the existing 5-methoxy-4,6-dichloropyrimidine generally includes Kjeldahl reaction, cyclization reaction, chlorination reaction, etc., the existing known 5-methoxy-4,6-dichloropyrimidine The preparation method of chloropyrimidine has the following some defects: one, with 2-methoxy-dimethyl malonate as starting raw material, and thiourea through condensation into mercaptopyrimidine ring, use Raney nickel demercapto group, obtain 4, 6-dihydroxy-5-methoxypyrimidine has a high solubility in wat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/60
CPCC07D239/60
Inventor 李涛
Owner CHANGSHU JINSHEN MEDICAL PROD CO LTD
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