2- (Piperidin-1-yl) pyrimidin-4 (3H) -ones characterized by having a 1,8-diazaspiro [4.5] deca-3-ene, 1-oxa-8-azaspiro [4.5] deca-3-ene, 2,8-diazaspiro [4.5] deca-3-ene, 2-oxa-8-azaspiro [4.5] deca-3-ene, 2,9-diazaspiro [5.5] undeca-3-ene, 1-oxa-9-azaspiro [5.5] undeca-3-ene, 1,9-diazaspiro [5.5] undeca-4-ene, or 3,9-diazaspiro [5.5] undeca-1-ene structure represented by general formula (1), or a pharmaceutically acceptable salt thereof.