The present invention provides a compound having a superior serotonin 5-HT2C receptor activating action, which is represented by the formulawherein A is —OR1 or —S(O)pR2, R1 and R2 are the same or different and each is a hydrogen atom, a hydrocarbon group optionally having substituent(s), or a heterocyclic group to optionally having substituent(s), and p is 0, 1 or 2, or a salt thereof.
