preparation method of quetiapine fumarate

The invention discloses a preparation method of quetiapine fumarate with high purity, which is suitable for industrialization and includes: taking 11-piperazine-dibenzo[B, F][1, 4]thiazepine dihydrochloride as the initial raw material, N-substituting and salt-forming to generate quetiapine fumarate. The highly finished product obtained by the method has high purity, the operating method is simple, the production cost is low, the yield is high, the preparation method is more suitable for industrialization, and the reaction time is shortened by adding a phase-transfer catalyst.