Method for preparing sulfadoxine

Abstract

The invention relates to a method for preparing sulfadoxine, and belongs to the field of the preparation of sulfanilamide antibacterial medicaments. The method comprises the following processes of: performing methyl oxidation reaction and refining, wherein the process of performing the methyl oxidation reaction comprises the following step of: adding methanol solution into a reaction kettle with a stirrer, adding sodium hydroxide, stirring to perform reflux reaction, recovering methanol until the solution is dried, adding water, continuing to recover the methanol, pressing feed liquid into a decoloration pot, regulating the pH value of the feed liquid, adding the water and a decolorizer into the feed liquid, keeping the temperature and decolorizing; and after decolorizing, performing filter pressing on the feed liquid by a filter press to a precipitation pot for precipitating, regulating the pH value of the feed liquid again, centrifuging, dehydrating, spin-drying and discharging to obtain a sulfadoxine crude product. The process of refining comprises the following steps of: adding the water into a dissolution pot, adding the sulfadoxine crude product with heating and stirring, adding calcium to obtain liquid to be decolorated, decolorating, performing the filter pressing on the decolorated liquid by the filter press to a crystallization pot, regulating the pH value, centrifuging, dehydrating to obtain a filter cake, centrifuging, spin-drying, discharging and drying to obtain a sulfadoxine finished product. The method has the advantages of high yield, stable quality of the finished product and high purity, and residues of a harmful solvent carried in the previous reaction process are reduced.

Description

technical field [0001] The invention belongs to the technical field of preparation of sulfonamide antibacterial drugs, and in particular relates to a preparation method of sulfadoxine. Background technique [0002] The chemical name of sulfadoxine (SDM) is: 4-(p-aminosulfonamide) 5,6-dimethoxypyrimidine; the English name is: Sulfadoxine; the Latin name is: Sulphamethoxinum or Sulfadimoxine; the molecular formula is C 12 h 14 o 4 N 4 S; molecular weight 310.33. [0003] Sulfadoxine, also known as Zhouxiao sulfonamide, sulfa-o-dimethoxine or 4-sulfa-5,6-dimethoxypyrimidine, is a white or off-white crystalline powder with a slightly bitter taste, odorless, and gradually changes color when exposed to light. Slightly soluble in water, methanol and ethanol, insoluble in ether, soluble in sodium hydroxide and dilute inorganic acids, belonging to sulfonamide antibacterial drugs. Sulfadoxine has the characteristics of long curative effect and low toxicity, and can tr...

AI Technical Summary

Problems solved by technology

[0007] However, the above-mentioned first method also has technical problems that people expect to solve but have not been solved so far, specifically: the reaction yield of the methoxidation step is low According to the "National Compilation of Raw Materials Processes 1980 Edition", it is recorded as 83.5%, and the yield in actual operation production is even lower, only about 80%

[0008] Through the analysis of the applicant for many years, the main cause of the above-mentioned low yield is that the raw material in the methoxidation reaction is 4-(p-aminobenzenesulfonamide group )-5-methoxy-6-chloropyrimidine failed to react completely

In addition, there is also the problem of unstable quality of finished products