Aromatic bicyclic compounds of formula (I) ##STR1## where R.sub.1 is specifically --H, CH.sub.3, --CH.sub.2 OH, --OH, --CHO, --CONH.sub.2, --COOH, --COOalkyl, --SH, S-alkyl, etc. . . . ; R.sub.2 is H; R.sub.3 is H, aryl, aralkyl or lower alkyl optionally substituted by a hydroxyl, a lower alkoxy or a --CO--R.sub.12, R.sub.12 being specifically H, lower alkyl, hydroxyl, lower alkoxy, or R.sub.2 and R.sub.3 together form a naphthalene ring with the benzene ring; R.sub.4 is a linear branched or unbranched alkyl having 1 to 15 carbon atoms or a cycloaliphatic radical; R.sub.5 represents specifically --(CH.sub.2).sub.n --R.sub.13, --CH.dbd.CH--(CH.sub.2).sub.n --R.sub.13, n being 0 or 1 to 6, R.sub.13 representing --COR.sub.15, monohydroxyalkyl, polyhydroxyalkyl, epoxy lower alkyl or --O--CO--R.sub.16, R.sub.15 representing specifically --OH, --Oalkyl, --Oaryl, R.sub.16 being specifically H, lower alkyl, aryl, or aralkyl; R.sub.6 and R.sub.7 are H, a halogen, lower alkyl or --OR.sub.16 ; and also the salts of the compounds of formula (I) in which R.sub.1 represents a carboxylic acid grouping; and the chiral analogues of the said compounds of formula (I).