The present invention addresses the problem of providing a novel compound that has an OX2R
agonist activity. The present invention relates to a substituted sulfonamide compound which is represented by formula (I) or a pharmacologically acceptable salt thereof. A compound according to the present invention, or a pharmacologically acceptable salt thereof, has an
agonist activity against OX2R, and is useful as, for example, a therapeutic agent for sleep disorders associated with OX2R (for example,
narcolepsy, idiopathic hypersomnia, Kleine-Levin syndrome, hypersomnia associated with a physical
disease, hypersomnia associated with a
mental disease, hypersomnia associated with a
drug or a substance,
circadian rhythm sleep-wake disorders, insufficient sleep syndrome, and extended sleep).