Process for preparing sulfadoxine

Abstract

A process for preparing sulfadoxine belongs to the preparation field of sulfonamides antibacterial agents. The process comprises a cyclization reaction and is characterized in that the cyclization reaction comprises the steps of adding a sodium methoxide solution into a reactor with a double helical ribbon stirrer; heating the solution while stirring; adding vaporific formamide and vaporific methyl ethyl methoxymalonate into the reactor at the same time in a spraying mode; controlling reaction temperatures; recovering solvents generated during reaction simultaneously; adding water for cooling and crystallizing after completing solvent recovery; centrifugally dripping; discharging; drying in vacuum; and obtaining 5-methoxy-4,6-dyhydroxy pyridine disodium. The process enables materials to diffuse, convect, cut, dislocate and radially move against one another, so that the effect of uniform mixing is achieved in a short time, reaction time is shortened, the reaction is completed, the purity of products are guaranteed, service lives of devices are prolonged, recycling time of solvents is shortened, resources are saved, and the high purity of the sulfadoxine which is the final product is guaranteed.

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

However, the cyclization reaction steps of CN102311393A, CN102304094A (preparation method of sulfonamide and its intermediate) and CN102304095A (preparation method of sulfonamide) have the following disadvantages: one is that it is difficult for the material to reach Uniform mixing effect, so it can only be compensated by prolonging the time, resulting in a lengthy reaction process and a waste of energy; the second is that formamide and methyl ethyl methoxymalonate are added dropwise to sodium methoxide, which is unreasonable property, causing the droplet particles to be coarse, increasing the difficulty of stirring and affecting the reaction effect (that is, it is difficult to completely react); the third is that it is difficult to ensure the purity of the product, because, due to the use of acid precipitation in the cyclization reaction, and the application of the mother liquor, the material ( product) becomes more viscous and easy to wrap impurities, and eventually bring impurities into the product; fourth, the use of acid analysis in the cyclization reaction will cause serious corrosion to the equipment; fifth, the recovery time of the solvent is long and consumes a lot of energy; sixth, the finished product Or it is difficult to say that the purity of the product sulfadoxine has no room or room for improvement