30 results about "FLUPIRTINE MALEATE" patented technology

The invention discloses a method for preparing flupirtine maleate with crystal form A and high bulk density, specifically dissolving flupirtine in a mixed solvent containing DMSO and solvent X, and then adding the maleic acid solution into the flupirtine solution , stirred, and after the crystals are fully separated, filtered, washed, and dried to obtain the high bulk density crystal A flupirtine maleate product. The flupirtine maleate prepared by the method of the invention has high bulk density, stable crystal form content, can meet the requirements of high-quality preparation production, has strong process repeatability, simple process condition requirements, low cost, and is more suitable for industrial production.

The invention discloses a method for preparing flupirtine maleate by a one-pot method. The method is characterized in that 2-amino-3-nitro-6-pyridine and 4-fluorobenzylamine serve as starting materials, and condensation, raney nickel reduction, ethyl chloroformate acylation and maleic acid salification are accomplished in a reactor without intermediate separation. The total yield of flupirtine maleate is increased from below 40% of a step-by-step method to above 70%, and the purity of a crude product is greater than 99%. According to the method, the technical flow is shortened, equipment is decreased, and the problem of high oxidation stain possibility of aminopyridine intermediates in a separation process is effectively solved. The feasibility and controllability of the one-pot method is proven by small-scale and pilot-scale studies, and the method is a handleable and environment-friendly manner to prepare flupirtine maleate, and is suitable for industrial production.

The invention discloses a synthesis method for a flupirtine maleate compound. The method comprises the steps that 2-amino-3-nitro-6-chloropyridine (a first compound) is used as a starting material to react with fluorobenzylamine (a second compound) to generate 2-amino-3-nitro-6-p-fluorobenzylamine pyridine (a third compound), the third compound is processed through di-tert-butyl dicarbonate ester protection to obtain 2-amino-3-nitro-6-p-fluorobenzylamine pyridine-3-based-tert-butyl acetate (a fourth compound), the fourth compound is processed through hydrogenation reduction and then react with ethyl chloroformate, after reacting is finished, deprotection is performed to obtain flupirtine hydrochloride (a fifth compound), and the fifth compound is salified with maleic acid to obtain flupirtine maleate (the sixth compound). According to the synthesis method, the starting material is cheap and easy to obtain, byproduct generation is avoided through amino protection, therefore, the impurity content is decreased, and the product quality is improved; catalytic reduction is performed by adopting palladium chloride, the reaction condition is mild, the reaction process is easy to operate, and the method is suitable for industrial production.