The invention relates to a compound selected from those of formula (I): ##STR1## in which R, R.sub.1, R.sub.2 and R.sub.3 are as defined herein for use in the treatment of a disorder of the melatoninergic system.
                            本发明涉及从以下式子(I)中选择的化合物:##STR1## 其中R,R.sub.1,R.sub.2和R.sub.3的定义如本文所述,用于治疗
褪黑激素系统的紊乱。