The invention relates to a preparation process for environment-friendly semisynthetic caffeine. According to the preparation process, preparation is carried out under the specific conditions like a temperature range of 90 to 160 DEG C, usage of an alkaline substance Y type zeolite as a catalyst, addition of a proper amount of surfactant substance Turkey red oil as an emulsifier and the like, and dimethyl carbonate (DMC) is used to replace limited toxic dimethyl sulphate (DMS); reaction yield is as high as 97.8%; and the quality of a caffeine product meets requirements.

Preparation process for environment-friendly semisynthetic caffeine

The invention discloses an environment-friendly refining method of theobromine, and relates to the technical field of synthetic chemistry. The method comprises the following steps: (1) dissolving a crude product to prepare a sodium salt; (2) carrying out decoloration; and (3) carrying out acidification and crystallization. According to the method provided by the invention, the theobromine in a theobromine crude product is converted into a sodium salt by adding a sodium hydroxide solution and insoluble impurities are filtered out; then, the decoloration effect is ensured by use of a decolorant,and pigment impurities are removed; and then, by controlling the pH value during acidification, the residual rate of theobromine in crystallization mother liquor can be reduced and the purity of theobromine in precipitated crystals can be increased. The prepared finished product of theobromine is white or creamy in appearance, and the residual rate of 3-methylxanthine is less than 0.15% or more,and meets requirements of the quality standard of theobromine; and the refining yield reaches 95% or more, thus reducing the loss amount of theobromine in a refining process.

Environment-friendly refining method of theobromine

The invention discloses a refining method for pentoxifylline recycling products. The content of impurities in the pentoxifylline recycling products can be reduced, after the recycling products are refined, the maximum single impurities are reduced to be 0.1% or below, the total impurities are 0.5% or below, the standard of finished pentoxifylline is met, the integral yield is improved, and the reaction cost is reduced. The refining method comprises the following steps: (1) adding water in the pentoxifylline recycling products under the condition of heating, dissolving, adding alkaline liquid to regulate a pH value to be 10-14, adding a reducing agent, insulating, and then cooling and filtering to obtain an alkaline solution, wherein the single impurities in the pentoxifylline recycling products are less than 5%, and the total impurities in the pentoxifylline recycling products are less than 10%; (2) fully mixing the alkaline solution obtained in step (1) with an organic solvent A, thenstanding for layering, and removing an organic phase by evaporation to obtain viscous liquid; and (3) adding an organic solvent B to dissolve the viscous liquid, adding activated carbon, after insulating, filtering the activated carbon, cooling filtrate to the temperature of 20 DEG C or below, and filtering and drying to obtain pentoxifylline.

Refining method for pentoxifylline recycling products

The invention provides a method for preparing theobromine. The method comprises the following steps: adding caffeine into a strong base solution to react to obtain caffeine carboxylic acid, reacting the caffeine carboxylic acid with sodium cyanate to obtain theobromine carboxylic acid, reacting the theobromine carboxylic acid with strong base to generate theobromine sodium salt in a closed loop manner, and neutralizing the theobromine sodium salt with weak acid so as to obtain theobromine. The theobromine can be prepared through the four steps, the process is simple, the production period is short, and experiment result shows that the yield of the theobromine prepared by using the method provided by the invention can be 48-50%, and the yield is high.

Method for preparing theobromine

The invention relates to a ring-closure reaction method of a caffeine intermediate 1,3-dimethyl-4-amino-5-formyl aminoureazine (FAU), and belongs to the technical field of synthesis and preparation of organic compounds. The method comprises the following step: carrying out a ring-closure reaction by catalyzing the 1,3-dimethyl-4-amino-5-FAU in water via an catalyst system containing ethyl amine, wherein the weight ratio of the dimethyl FAU to the water to the catalyst system is 1 to (4-8) to (0.5-2). The ring-closure reaction method can be used for obviously increasing the yield of theophylline, and is low in environment-friendly treating pressure and production cost, high in quality of the caffeine intermediate 1,3-dimethyl-4-amino-5-FAU, moderate in reaction condition, as well as simple and convenient to operate, and reaction conditions are easily controlled.

Ring-closure reaction method of caffeine intermediate 1,3-dimethyl-4-amino-5-formyl aminoureazine (FAU)

A process for preparing theobromine by methylating 3-methyl xanthine disodium salt comprises reacting 3-methyl xanthine disodium salt with dimethyl sulfate by using acetone as solvent in the presence of sodium carbonate and acidifying. The present application also provides a process for refining theobromine which comprises dissolving coarse theobromine in liquid alkaline solution, decolorizing, filtering, adding reducing agent in filtrate, and acidifying at 60-80 °C until pH is 5-6, filtering, and drying to obtain theobromine.

Nissim Bilman

Papers

Theobromine production process