The invention provides a compound of Formula I, an isomer, a pharmaceutically acceptable salt, or a solvate thereof, and use thereof in manufacture of a medicament for preventing and/or treating a drug-resistant tumor or disease or disorder caused by a drug-resistant bacterium, or use thereof in manufacture of a medicament for preventing and/or treating a tumor, a neurodegenerative disease, an allogeneic graft rejection, or an infection-associated disease or disorder; preferably, the tumor, neurodegenerative disease, allogeneic graft rejection, or infection-associated disease or disorder is a disease or disorder caused by Heat shock protein 70 (Hsp70). The compounds of the invention, which are a class of Hsp70 inhibitors having a novel structure and a high activity, solve the problem concerning drug resistance of tumors, enhance the effect of treating tumors, and provide a new medical strategy for treatment of tumors in clinic.