Preparation method of citalopram diol intermediate hydrobromide, citalopram diol intermediate hydrobromide and citalopram

The invention is applicable to the technical field of synthesis of medical intermediates, and provides a preparation method of citalopram diol intermediate hydrobromide, citalopram diol intermediate hydrobromide and citalopram. The preparation method comprises the following steps: introducing bis (dimethylaminoethyl) ether, p-fluorophenyl magnesium halide and N, N-dimethylaminopropyl magnesium halide into 5-cyanophthalide serving as a raw material to perform Grignard reaction in an organic solvent, and introducing hydrobromic acid to react to form salt after the reaction is finished, thereby obtaining the product. The total yield of 15kg-grade amplification preparation reaches 87%, the purity is 99.73%, a passivation reagent bis (dimethylaminoethyl) ether is introduced into a Grignard reaction system, the selectivity and the yield of the Grignard reaction are remarkably improved, and the method is small in dosage of the passivation reagent, low in cost and environmentally friendly; compared with a binary solv