Preparation method of 4', 6-diamidinyl-2-phenylindole dihydrochloride

The invention discloses a preparation method of 4', 6-diamidinyl-2-phenylindole dihydrochloride, which comprises the following steps: firstly, taking 6-substituted indole as a raw material, and reacting with formamide under the action of a reaction solvent and a first catalyst to prepare 6-cyano indole; then performing a reactionthe 6-cyanoindole and the 4-substituted cyanobenzene under the action of a second catalyst, and obtaining 6-cyano-2-(4 '-cyanophenyl) indole; using 6-cyano-2-(4'-cyanophenyl) indole as a raw material and reacting with alcohol containing a substituent group under the action of a third catalyst, and obtaining 4', 6-bis (substituent group-containing methyleneimic acid ester)-2-phenylindole dihydrochloride; finally, continuously reacting with ammonium chloride, and obtaining the 4', 6-diamidinyl-2-phenylindole dihydrochloride. The design route is reasonable in design, the process safety is high, the method is friendly to operators, the cost is low, and the requirement for industrial produ