The present invention provides compounds having a Toll-like receptor 4 (TLR4) signaling inhibitory action useful as preventive and therapeutic drugs of inflammatory disease and/or central nervous system disease or diseases such as chemotherapy-induced peripheral neuropathy (CIPN), chemotherapy-induced neuropathic pain (CINP), liver injury, ischemia-reperfusion injury (IRI) and the like. The present invention relates to a compound represented by formula (I) and a salt thereof: wherein, each symbol is explained in greater detail in the specification.