Preparation method for high-purity pomalidomide

A preparation method for high-purity pomalidomide comprises the following steps: (1) adding 3-nitro-N-(2,6-dioxo-3-piperidyl)phthalimide, palladium carbon and N-methyl pyrrolidone to a reaction kettle, vacuumizing, then introducing hydrogen gas, carrying out suction filtration after a reaction is complete, adding medicinal charcoal to the filtrate, stirring, heating, and carrying out suction filtration; and (2) adding an alkaline aqueous solution to the filtrate finally obtained in the step (1), stirring, then adding purified water, cooling and crystallizing, carrying out suction filtration, adding purified water to the obtained filter cake, stirring, carrying out suction filtration, washing, and drying to obtain the high-purity pomalidomide product. The preparation method provided by the invention has the advantages of simple operation and mature and stable technology, and can significantly improve the quality of pomalidomide; the purity of the obtained product is greater than 99.5%, the contents of single i