The invention relates to compounds of formula (I):
1
wherein:
R
1
, R
2
and R
3
are as defined in the description,
X is as defined in the description,
Y represents an oxygen atom, a sulphur atom, a C(H)q group, SO or S0
2
,
n is equal to from 0 to 5,
A represents a NR
5
R
6
or CZNR
8
R
9
group.
and medicinal products containing the same are useful in treating or in preventing melatoninergic disorders.