Synthetic process of Selinexor intermediate

The invention provides a synthetic process of a Selinexor intermediate. The synthetic process comprises the following steps of: after inputting an intermediate 2 and -N,N'-dimethylformamide into a reaction kettle, adding sodium hydroxide; then adding magnesium chloride hexahydrate; stirring the mixture for 2-4h; adjusting the pH of a reaction system with hydrochloric acid to 1.8-2.2; performing extraction and concentration to obtain an intermediate 5; inputting the intermediate 5 and methanol into the reaction kettle; dropwise adding formylhydrazine and ethyl formate; raising the temperature to 90-95 DEG C; performing a reaction for 6-8 h; adding water after cooling; performing washing, concentration and filtration; and drying the mixture to obtain the Selinexor intermediate. According to the method, sodium hydrosulfide is not used, so that toxic gas hydrogen sulfide is no longer generated, and the synthetic process is small in environmental pollution and suitable for industrial production.