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Preparation method of 5-methoxy-4,6-dichloropyrimidine

A technology of sodium methoxypyrimidine and dichloropyrimidine, which is applied in the field of preparation of cyclic sulfonamide intermediates, can solve problems such as cross-temperature, incompatible with environmental protection, unfavorable reaction temperature, etc., and achieves reduction of production cost and personal safety. the effect of the threat

Inactive Publication Date: 2014-07-09
CHANGSHU NANHU INDAL CHEM
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  • Claims
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Problems solved by technology

However, when the above reaction is added with 4,6-dihydroxy-5-methoxypyrimidine sodium, it is easy to have a sudden temperature series phenomenon, about ten to twenty minutes, which is not conducive to the control of the reaction temperature; the most important thing is to use a rapid Poisonous phosphorus oxychloride seriously threatens the health of operators and does not meet the national planning and requirements for environmental protection

Method used

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  • Preparation method of 5-methoxy-4,6-dichloropyrimidine
  • Preparation method of 5-methoxy-4,6-dichloropyrimidine
  • Preparation method of 5-methoxy-4,6-dichloropyrimidine

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preparation example Construction

[0026] The preparation method of 5-methoxy-4,6-dichloropyrimidine of the present invention comprises the following steps: (a) adding phosphorus trichloride into the reaction vessel, and raising the temperature to 70-80°C, and adding to the reaction vessel within 0.5-1.5 hours Add 4,6-dihydroxy-5-methoxypyrimidine sodium, control the temperature at 80-95°C, and then reflux at 110-120°C for 2-6 hours to obtain a reaction mixture; (b) the The mixture is cooled to below 90°C, and an organic solvent is added to stir and dissolve, then poured into deionized water for hydrolysis, and left to separate to form the first water layer and the first organic solvent layer; (c) adding the first organic solvent to the adding lye to the layer to adjust the pH value to 6.5-7, and standing again to form a second water layer and a second organic solvent layer; (d) taking the second organic solvent layer and distilling off the organic solvent therein. On the one hand, the use of phosphorus trichlo...

Embodiment 1

[0030] This example provides a preparation method of 5-methoxy-4,6-dichloropyrimidine, and the specific feeding ratio is shown in Table 1:

[0031] Table 1 Reaction raw materials and their feeding ratio

[0032]

[0033] The specific operation process is as follows:

[0034] (a) Add 825kg of phosphorus trichloride into the dry chlorination reaction pot, turn on the reflux and hydrogen chloride gas absorption device, heat the steam to 70°C, turn off the steam and naturally raise the temperature to 80°C, and slowly add 4,6-dihydroxy- 5-Methoxypyrimidine sodium, control the addition speed so that the addition time is 0.5-1.5 hours, and the internal temperature is controlled at 80-95°C; heat the chlorination reaction pot, and reflux at 110-120°C for 4 hours;

[0035] (b) Distill under reduced pressure and reclaim phosphorus oxychloride (350kg) until the reaction residue is dry; close the steam valve, cool to below 90°C, add 900L trichlorethylene, stir and dissolve; put 1500Kg ...

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Abstract

The invention relates to a preparation method of 5-methoxy-4,6-dichloropyrimidine. The preparation method comprises following steps: (a) phosphorus trichloride is delivered into a reaction container, 4,6-dihydroxy-5-methoxypyrimidine sodium is added with uniform speed in 0.5 to 1.5h, and an obtained mixed material is subjected to reflux reaction at a temperature of 110 to 120 DEG C for 2 to 6h so as to obtain a reaction mixture; (b) the reaction mixture is cooled to a temperature below 90 DEG C, an organic solvent is added, an obtained material is stirred so as to realize dissolving, deionized water is added for hydrolysis, and an obtained product is allowed to stand so as to obtain a first water layer and a second organic solvent layer; (c) alkali liquor is added into the first organic solvent layer so as to adjust pH value to 6.5 to 7, an obtained mixture is allowed to stand so as to obtain a second water layer and a second organic solvent layer; and (d) the second organic solvent layer is subjected to distillation so as to remove the solvent. According to the preparation method, phosphorus trichloride is used for replacing hypertoxic phosphorus oxychloride, so that production cost is reduced, and threats of chemicals on personal safety of operators are reduced.

Description

technical field [0001] The invention relates to a preparation method of a sulfonamide intermediate, in particular to a preparation method of 5-methoxy-4,6-dichloropyrimidine. Background technique [0002] Sulfonamide, whose chemical name is 4-(p-aminobenzenesulfonyl)-5,6-dimethoxypyrimidine, is generally used for the treatment of inflammation, such as upper respiratory tract infection tonsillitis, bacillary enteritis, skin infection, etc. It can be used in conjunction with other drugs to treat pulmonary tuberculosis and lymphatic tuberculosis. Sulfonamide has experienced several generations of research and development, and its production process has gradually stabilized, specifically the following preparation steps: Step (1): [0003] [0004] Step (2): [0005] [0006] Step (3): [0007] [0008] Step (4): [0009] [0010] [0011] Step (5): [0012] [0013] Wherein, 5-methoxy-4,6-dichloropyrimidine is an intermediate prepared in step (3), and its ...

Claims

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Application Information

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IPC IPC(8): C07D239/34
CPCC07D239/34
Inventor 邵香民
Owner CHANGSHU NANHU INDAL CHEM
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