Spiro aromatic ring compound and application thereof

A compound of Formula:

• or a pharmaceutically acceptable salt thereof, or an enantiomer, diastereoisomer, tautomer, solvate, isotope-substituted derivative, polymorph, prodrug or metabolite thereof, wherein:
• X1 and X2 are independently selected from a bond, CRaRb or NRc;
• X3 is selected from a bond, CRaRb, NRc, S or o;
• Ra, Rb and Rc are independently selected from H, halogen, substituted or unsubstituted C1-8 alkyl, or substituted or unsubstituted C1-6 alkoxyl;
• X4 is N or CH;
• R1, R2, R3, and R4 are independently selected from H, —OH, halogen, substituted or unsubstituted amino, substituted or unsubstituted C1-6 alkyl, or substituted or unsubstituted C1-6 alkoxyl;
• and R1, R2, R3, and R4 cannot be —OH or —NH2 simultaneously;
• ring A is selected from substituted or unsubstituted 5 to 10-membered heteroaryl, wherein the heteroaryl comprises 1-3 heteroatoms selected from:
• N, O, S or P;
• ring C is
• X5, X6, X7, X8 and X9 are independently selected from N or CRd;
• and at most 3 of X5, X6, X7, X8 and X9 are N simultaneously;
• X10, X11, X12, X13, X14, X15, X16 and X17 are independently selected from N or CRd;
• and at most 5 of X10, X11, X12, X13, X14, X15, X16 and X17 are N simultaneously;
• X18, X19, X20 and X21 are independently selected from N or CRd, and at most 3 of X18, X19, X20 and X21 are N simultaneously;
• R6 and R8 are independently selected from —NH2, —CN, —OH, —NO2, halogen, unsubstituted or halogenated C1-6 alkyl, or unsubstituted or halogenated C1-6 alkoxyl;
• and
• Rd is selected from H, halogen, unsubstituted or halogenated C1-6 alkyl, or unsubstituted or halogenated C1-6 alkoxyl;
• n is any integer from 1 to 3;
• and
• wherein the term “substituted” refers to one or more hydrogen atoms on the group are substituted by a substituent selected from:
• halogen, —OH, —NO2, —NH2, —N(unsubstituted or halogenated C1-6 alkyl)2, —CN, unsubstituted or halogenated C1-8 alkyl, unsubstituted or halogenated C1-8 alkoxyl, unsubstituted or halogenated C1-8 alkoxyl-C1-8 alkyl, unsubstituted or halogenated C3-8 cycloalkyl-C1-8 alkyl, unsubstituted or halogenated C1-6 alkyl carbonyl, unsubstituted or halogenated C1-6 alkoxyl carbonyl, hydroxamic acid group, unsubstituted or halogenated C1-6 alkyl thiol, —S(O)2N (unsubstituted or halogenated C1-6 alkyl)2, —S(O)2 (unsubstituted or halogenated C1-6 alkyl), —N(unsubstituted or halogenated C1-6 alkyl)S(O)2N (unsubstituted or halogenated C1-6 alkyl)2, —S(O)N (unsubstituted or halogenated C1-6 alkyl)2, —S(O)(unsubstituted or halogenated C1-6 alkyl), —N(unsubstituted or halogenated C1-6 alkyl)S(O)N (unsubstituted or halogenated C1-6 alkyl)2, or —N(unsubstituted or halogenated C1-6 alkyl)S(O)(unsubstituted or halogenated C1-6 alkyl).