A fused pyrazolyl compound having an anti-tumor potency of the following formula is synthesized: wherein A is in which n is 0, 1, 2, or 3; Ar1 is benzene, thiophene or furan; Ar2 is furyl; and Ar3 is phenyl; R1 and R2 independently are hydrogen, halogen or —(CH2)mORe; R3 is hydrogen or alkyl; R4 is —(CH2)r-A1, wherein r is an integer of 1-5, and A1 has a formula of —O—C(O)—(CRcH)q—NRc′Rd′; R5 and R6 independently are hydrogen, halogen, or alkyl, or R5 and R6 together are —O(CH2)mO—; Rc is H, halogen, nitro, cyano, alkyl, or aryl; Re is H, alkyl, or aryl; Rc′ and Rd′ independently are H, alkyl, or aryl; m is 0, 1, 2, 3, 4, 5, or 6; and q is 1, 2, 3, 4, 5, or 6; or a salt thereof.