A compound represented by the following Formula (l), or a pharmaceutically acceptable salt thereof: wherein, R 1 is hydroxy or C 1 -C 10 alkoxy; X is N or O; R 2 is -(CH 2) p -5- to 12-membered heterocycle-(CH 2) p -C 6 -C 12 aryl, 5- to 12-membered heterocycle, -(CH 2) p -NHC(=O)-C 6 -C 12 aryl, -CHR 4 R 5, 5- to 12-membered heteroaryl, C 6 -C 12 aryl, -C 6 -C 12 aryl-O-5- to 12-membered heteroaryl, or -(CH 2) p -5- to 12-membered heteroaryl, wherein p is an integer of 1 to 10; R 4 and R 5 are each independently C 1 -C 6 alkoxycarbonyl or -CH 2 -5- to 12-membered heteroaryl; said heterocycle and heteroaryl may contain 1 to 3 heteroatoms selected from N, O and S; when R 2 is -(CH 2) p -5- to 12-membered heterocycle-(CH 2) p -C 6 -C 12 aryl, said aryl can be substituted with 1 to 4 substituents which are halogen, when R 2 is 5- to 12-membered heterocycle, said heterocycle is substituted with 1 to 4 substituents which are oxo, when R 2 is -(CH 2) p -NHC(=O)-C 6 -C 12 aryl, said aryl can be substituted with 1 to 4 substituents which are hydroxy, when R 2 is 5- to 12-membered heteroaryl, said heteroaryl is substituted with 1 to 4 substituents selected from the group consisting of oxo, aminocarbonyl and C 1 -C 6 alkyl, when R 2 is C 6 -C 12 aryl, said aryl is substituted with 1 to 4 substituents selected from the group consisting of C 1 -C 6 alkyl, nitro and C 1 -C 6 alkoxy, when R 2 is -C 6 -C 12 aryl-O-5- to 12-membered heteroaryl, said heteroaryl can be substituted with 1 to 4 substituents which are C 1 -C 6 alkylaminocarbonyl, and when R 2 is -(CH 2) p -5- to 12-membered heteroaryl, said heteroaryl is substituted with 3 substituents which are C 1 -C 6 alkyl, hydroxy and hydroxy-C 1 -C 6 alkyl, respectively; R 3 is hydrogen; when X is O, R 3 does not exist; when X is N, X taken together with R 2 and R 3 may form a 5- to 12-membered heterocycle containing 1 to 3 heteroatoms selected from O, N and S; wherein said heterocycle is substituted with C 6 -C 12 aryl; a 6- to 12-membered heteroaryl containing 1 to 3 heteroatoms selected from O, N and S, which is unsubstituted or substituted with halogen; or -O-CHR 6 R 7; and wherein R 6 and R 7 are each independently C 6 -C 12 aryl or a 6- to 10-membered heteroaryl containing 1 to 3 heteroatoms selected from N, O and S, both of which are unsubstituted or substituted with halogen. R 1 is hydroxy or C 1 -C 10 alkoxy; X is N or O; R 2 is -(CH 2) p -5- to 12-membered heterocycle-(CH 2) p -C 6 -C 12 aryl, 5- to 12-membered heterocycle, -(CH 2) p -NHC(=O)-C 6 -C 12 aryl, -CHR 4 R 5, 5- to 12-membered heteroaryl, C 6 -C 12 aryl, -C 6 -C 12 aryl-O-5- to 12-membered heteroaryl, or -(CH 2) p -5- to 12-membered heteroaryl, wherein p is an integer of 1 to 10; R 4 and R 5 are each independently C 1 -C 6 alkoxycarbonyl or -CH 2 -5- to 12-membered heteroaryl; said heterocycle and heteroaryl may contain 1 to 3 heteroatoms selected from N, O and S; when R 2 is -(CH 2) p -5- to 12-membered heterocycle-(CH 2) p -C 6 -C 12 aryl, said aryl can be substituted with 1 to 4 substituents which are halogen, when R 2 is 5- to 12-membered heterocycle, said heterocycle is substituted with 1 to 4 substituents which are oxo, when R 2 is -(CH 2) p -NHC(=O)-C 6 -C 12 aryl, said aryl can be substituted with 1 to 4 substituents which are hydroxy, when R 2 is 5- to 12-membered heteroaryl, said heteroaryl is substituted with 1 to 4 substituents selected from the group consisting of oxo, aminocarbonyl and C 1 -C 6 alkyl, when R 2 is C 6 -C 12 aryl, said aryl is substituted with 1 to 4 substituents selected from the group consisting of C 1 -C 6 alkyl, nitro and C 1 -C 6 alkoxy, when R 2 is -C 6 -C 12 aryl-O-5- to 12-membered heteroaryl, said heteroaryl can be substituted with 1 to 4 substituents which are C 1 -C 6 alkylaminocarbonyl, and when R 2 is -(CH 2) p -5- to 12-membered heteroaryl, said heteroaryl is substituted with 3 substituents which are C 1 -C 6 alkyl, hydroxy and hydroxy-C 1 -C 6 alkyl, respectively; R 3 is hydrogen; when X is O, R 3 does not exist; when X is N, X taken together with R 2 and R 3 may form a 5- to 12-membered heterocycle containing 1 to 3 heteroatoms selected from O, N and S; wherein said heterocycle is substituted with C 6 -C 12 aryl; a 6- to 12-membered heteroaryl containing 1 to 3 heteroatoms selected from O, N and S, which is unsubstituted or substituted with halogen; or -O-CHR 6 R 7; and wherein R 6 and R 7 are each independently C 6 -C 12 aryl or a 6- to 10-membered heteroaryl containing 1 to 3 heteroatoms selected from N, O and S, both of which are unsubstituted or substituted with halogen.