Novel chlorin e6-folic acid conjugate, preparation method thereof, and a pharmaceutical composition for the treatment of cancer comprising the same

A method for preparing a chlorin e6-folic acid conjugate that is represented by the following Formula 1 or 2, or a pharmaceutically acceptable salt thereof, comprising the steps of:

• reacting folic acid with [tert-butyl-N-(6-aminohexyl)]carbamate or tert-butyl 2-(2-(2-aminoethoxy)ethoxy)ethylcarbamate under a nitrogen atmosphere at room temperature to obtain γ-{[tert-butyl-N-(6-aminohexyl)]carbamate}folic acid or γ-{N-{2-[2-(2-aminoethoxy)ethoxy]ethyl carbamate}folic acid;
• treating γ-{[tert-butyl-N-(6-aminohexyl)]carbamate}folic acid or γ-{N-{2-[2-(2-aminoethoxy)ethoxy]ethyl carbamate}folic acid of the above step with trifluoro-acetic acid to obtain γ-(6-aminohexyl)folic acid or γ-{N-{2-[2-(2-aminoethoxy)ethoxy]ethyl}}folic acid;
• adding N-hydroxysuccinimide and dicyclohexylcarbodiimide to chlorin e6 in the dark under a nitrogen atmosphere to obtain chlorin e6 succinidyl ester;
• and
• adding chlorin e6 succinidyl ester to the prepared γ-(6-aminohexyl)folic acid or γ-{N-{2-[2-(2-aminoethoxy)ethoxy]ethyl}}folic acid in the dark under a nitrogen atmosphere to prepare [γ-(6-aminohexyl)folic acid]-chlorin e6 or {γ-{N-{2-[2-(2-aminoethoxy)ethoxy]ethyl}folic acid}}-chlorin e6.