| abstract |
The present invention discloses a compound represented by the following formula or a salt thereof, useful as a prophylactic / therapeutic agent for diseases associated with melatonin activity:n n n n n n n n [In the meal,n n n R 1 represents an optionally substituted hydrocarbon group, optionally substituted amino, optionally substituted hydroxy or optionally substituted heterocyclic group;n n n R 2 represents a hydrogen atom or an optionally substituted hydrocarbon group;n n n R 3 represents a hydrogen atom, a halogen atom, an optionally substituted hydrocarbon group, an optionally substituted amino, an optionally substituted hydroxy or an optionally substituted mercapto;n n n Xa to Xe each represent a carbon atom or a nitrogen atom;n n n m represents a number from 0 to 2; Andn n n Ring A to ring C each represent an optionally substituted ring. |