The invention relates to a compound selected from those of formula (I): ##STR1## in which Ar', R.sub.1 and R.sub.2 are as defined in the specification, an optical isomer, and an addition salt thereof with a pharmaceutically-acceptable acid or base. Medicinal product which is useful in treating or in preventing a disorder of the melatoninergic system.
本发明涉及选择自式(I)的化合物:##STR1## 其中Ar',R.sub.1和R.sub.2如规范中所定义,光学异构体及其与药学上可接受的酸或碱的加合盐。该药物产品可用于治疗或预防
褪黑激素系统紊乱。