Novel tricyclic derivative or pharmaceutically acceptable salts thereof, preparation method thereof, and pharmaceutical composition containing the same

A tricyclic derivative represented by chemical formula 1 or pharmaceutically acceptable salts thereof:

• wherein Y1, Y2 and Y3 are independently H, C1˜C10 straight or branched chain alkyl, hydroxy, C1˜C10 alkoxy, —COOR′, —NR2R3 or -A-B;
• A is —O—, —CH2—, —CH(CH3)—, —CH═N— or —CONH—;
• B is —(CH2)n1-Z, —(CH2)n2-NR2R3 or —(CH2)n3-OR1;
• Z is C5˜C20 aryl non-substituted or substituted with R5 and selectively R6, C3˜C10 cycloalkyl non-substituted or substituted with R5 and selectively R6, C1˜C20 heterocyclic compound non-substituted or substituted with R5 and selectively R6;
• R1 is H or C1˜C10 straight or branched chain alkyl;
• R2 and R3 are independently H, C1˜C10 straight or branched chain alkyl or —(CH2)n4R7;
• R5 is H, C1˜C10 straight or branched chain alkyl, C5˜C20 aryl or C1˜C20 heterocyclic compound;
• R6 is H or C1˜C10 straight or branched chain alkyl;
• R7 is —NR8R9, —COOR1, —OR1, —CF3, —CN, halogen or Z;
• R8 and R9 are independently H or C1˜C10 straight or branched chain alkyl;
• n1 to n4 are respectively integers between 0 and 15;
• Y4 is H or C1˜C10 straight or branched chain alkyl.