Preparation method of selenium-containing heterocyclic compounds

A preparation method of a selenium-containing heterocyclic compound, comprising the following steps:

• sequentially adding azacyclopropane derivative of formula I, selenium powder, trimethylsilyl cyanide (TMSCN) and an organic solvent to a reactor equipped with a magnetic stirrer,
• subsequently replacing atmosphere in the reactor with an inert atmosphere, heating and stirring for reaction to obtain a reaction mixture,
• diluting the reaction mixture with ethyl acetate after the reaction, and then filtering through a silica gel pad to obtain a filtrate,
• concentrating the filtrate under a reduced pressure to obtain a residue, and then purifying the residue by silica flash chromatography, thereby obtaining a selenium-containing heterocyclic compound of formula II;
• wherein a formula for the reaction is as follows:
• where n=0, 1, or 2;
• where R1, R2 and R3 represent substituent groups on a connected ring, which are independently selected from the groups consisting of hydrogen group, C1-20 alkyl group, C6-20 aryl group, C3-20 cycloalkyl group, and C6-20 aryl-group-C1-20 alkyl-group;
• or adjacent two of which being R1/R2, R2/R2, R2/R3 or R1/R3 substituent groups are connected to each other and form one of saturated or unsaturated five to seven membered carbon rings together with carbon atoms connecting the adjacent two substituent groups;
• wherein the organic solvent is one selected from alcoholic solvents.