3 results about "Free base" patented technology

The invention discloses a novel sorafenib tosylate polycrystalline form A and a preparation method thereof. A DSC spectrum of the crystal form comprises a transition peak at 198.0-207.5 DEG C and a melting decomposition peak at 238.5-247.5 DEG C. The invention also discloses a method for preparing the sorafenib tosylate (I) polycrystalline form A from sorafenib free base and p-toluenesulfonic acid in a mixed solvent of alcohol and water. The method has the advantages of good repeatability, simple operation, high product yield, high purity, and suitability for industrialized productions.

The invention discloses a preparation method of amlodipine maleate. The preparation method is applied in the field of pharmaceutical synthesis and uses maleic acid and amlodipine free base as starting raw materials. The preparation method comprises the following steps: adding maleic acid in anhydrous methanol or mother liquor, heating to dissolve, filtering to obtain the methanol solution of maleic acid, and adding the solution in a reaction bottle of a finished product area; adding amlodipine free base in anhydrous methanol to dissolve, stirring to ensure that amlodipine free base is completely dissolved and is transparent, and cooling to obtain the methanol solution of amlodipine free base; slowly adding the methanol solution of amlodipine free base in the obtained methanol solution of maleic acid, keeping the temperature and stirring, cooling, and standing to precipitate crystals; and washing the obtained crystals with absolute alcohol, and drying to obtain the finished product. In the preparation method, the solvent used for forming amlodipine maleate is greatly improved, an anhydrous methanol reaction system is established, the crystal form of the finished product is greatly improved, vacuum filtration is easy, and the yield is increased; and the mother liquor obtained through crystallization and filtration is used as the solvent for dissolving the next batch of solid amlodipine, thus the use amount of anhydrous methanol can be reduced, the utilization rate of the solvent can be increased, the treatment cost of the solvent can be saved, the drying time can be shortened and the operation time can be greatly shortened.

The invention relates to a novel method for removing the methyl impurity in the preparation of asenapine. According to the method, asenapine maleate is taken as the raw material, then asenapine maleate is decomposed, the free alkalis and ethyl chloroformate are refluxed in toluene, and the product reacts with hydrobromic acid under reflux to obtain the methyl-free asenapine product. The method has the advantages of high yield and simple and convenient operation.