- Method for synthesizing caffeine
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The invention discloses a method for synthesizing caffeine, and relates to the technical field of preparation of heterocyclic compounds containing purine ring systems. The preparation method comprisesthe following steps: mixing cyanoacetic acid and acetic anhydride at 30-80 DEG C for reaction, adding a solvent and dimethylurea, cooling to room temperature after reflux reaction is finished, filtering, concentrating filtrate, combining solids to obtain dimethylacetamide, adding liquid caustic soda to adjust the pH to 8-11, and reacting at 80-100 DEG C to generate dimethyl 4AU; the method comprises the following steps: completely dissolving dimethyl 4AU in formic acid, adding sodium nitrite, reacting at room temperature, adding a catalyst, keeping the temperature at 30-70 DEG C, recovering the catalyst after the reaction is finished, and concentrating mother liquor to recover formic acid, thereby obtaining dimethyl FAU; adding water and liquid caustic soda into dimethyl FAU, and carryingout a ring-closure reaction to obtain theophylline sodium salt; the theophylline sodium salt is subjected to methylation reaction and refining to obtain caffeine. The method has the advantages of accessible raw materials, mild and controllable reaction conditions, fewer steps, high yield and greatly higher product quality, is simple to operate, and can easily implement industrial production.
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- Synthesis method of theophylline
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The invention discloses a synthesis method of theophylline, and relates to the technical field of preparation of heterocyclic compounds containing purine ring systems. The preparation method comprisesthe following steps: mixing cyanoacetic acid and acetic anhydride at 30-80 DEG C for reaction, adding a solvent and dimethylurea, cooling to room temperature after reflux reaction is finished, filtering, concentrating filtrate, combining solids to obtain dimethylacetamide, adding liquid caustic soda to adjust the pH to 8-11, and reacting at 80-100 DEG C to generate dimethyl 4AU; completely dissolving dimethyl 4AU in formic acid, adding sodium nitrite, reacting at room temperature, adding a catalyst and water, keeping the temperature at 30-70 DEG C, recovering the catalyst after the reaction is finished, and concentrating mother liquor to recover formic acid, thereby obtaining dimethyl FAU; adding dilute sulfuric acid into the dimethyl FAU to adjust the pH value to 36, heating to 90-100 DEG C, allowing the feed liquid to pass through an ozone reactor and a decolorizer, crystallizing by a crystallizer, and carrying out cold filtration to obtain theophylline. The method has the advantages of few reaction steps, mild reaction conditions, simple operation, high yield, stable product quality, small discharge capacity, reduction of the environmental protection treatment difficulty, and easy industrialization.
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- Preparation method of theophylline sodium salt
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The invention relates to the technical field of pharmaceutical chemicals, and particularly discloses a preparation method of theophylline sodium salt. The preparation method of theophylline sodium salt comprises the following process steps: mixing cyanoacetic acid and acetic anhydride for reaction to obtain mixed anhydride, and performing a condensation reaction on the mixed anhydride and 1,3-dimethylurea to obtain 1,3-dimethyl cyanoacetylurea; sequentially carrying out cyclization, nitrosation, hydrogenation and acylation on the 1,3-dimethyl cyanoacetylurea to obtain 1,3-dimethyl-4-amino-5-formylamino uracil; subjecting the 1,3-dimethyl-4-amino-5-formylamino uracil to ring closing to obtain the theophylline sodium salt. According to the preparation method, the reaction conditions are mildand easy to control, the product yield is high, byproducts are few, strong ammonia gas smell is avoided, the cost is low, and generated pollution wastes are few.
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