A compound of the formula wherein R1 and R2 are H, a hydrocarbon group or a heterocyclic group, or R1 and R2 are combinedly a spiro ring; R3 is a hydrocarbon group, a substituted amino group, a substituted hydroxyl group or a heterocyclic group; R4 is H or alkyl; ring A is a substituted benzene ring; m and n denote 1 to 4; {overscore (.........)} means a single or double bond or a salt, a process of producing thereof and a composition having a binding affinity for melatonin receptor.