Compounds of formula (I): ##STR1## in which: n represents 1 or 2,R.sub.1 represents hydrogen or alkyl, benzyl, acetyl, benzoyl, allyl, pyridinecarbonyl, pyridinemethyl, acylaminoalkyl (optionally substituted), pyridineaminocarbonyl, phthalimidoalkyl, thiochromanyloxyalkyl or (benzodioxanyloxy)alkyl,R.sub.2, R.sub.3 or R.sub.4, which may be identical or different, represent hydrogen or halogen or alkyl, alkoxy, hydroxyl, acetyl, aminocarbonyl, aminomethyl, cyano, nitro, amino, phenyl (which may or may not be substituted), furyl, pyridinyl, thienyl or pyridyl, or alternatively, when they are located on adjacent carbons, R.sub.2 and R.sub.3 form, with the carbon atoms which bear them, a furan or phenyl ring,the isomers thereof and the addition salts thereof with a pharmaceutically acceptable acid, and medicinal products containing the same are useful for the treatment of diseases requiring a ligand to the 5-HT.sub.2C receptors.