abstract |
The invention belongs to the technical field of medicinal chemistry and relates to a method for purifying sildenafil free base, in particular to a purification method for removing new impurities from sildenafil free base. The method of the present invention comprises the following steps: take the crude product of sildenafil free base (II), add 1-6 times the amount (v/w) of organic solvent, heat up to 40-60°C after fully stirring, and keep stirring 1-6h, then cooled to room temperature, filtered, and dried to obtain the fine product of sildenafil free base (II). |