1,1a, 5,5a-tetrahydro-3-thia-cyclopropa (a) pentalenos: tricyclic thiophene derivatives as agonists of S1P1 / EDG1 receptor.

A compound selected from the group consisting of thiophenes of the formula (I) (see formula) wherein A represents -CH2CH2-, -CH = CH-, -NH-CH2-, -CH2-O- or -CH 2 NH-; R 1 represents hydrogen or alkyl; in the case X represents CR 4, R 1 in addition represents halogen; and in the case A represents -CH2-CH2- or -CH2NH-, R1 in addition represents alkoxy; R 2 represents hydrogen, alkoxy, fluoro-alkoxy, hydroxy-alkoxy, hydroxy-alkyl, di- (hydroxyalkyl) -alkyl, di- (hydroxyalkyl) -alkoxy, 1-glyceryl, 2-glyceryl, pyridin-3 -yl-methoxy, or pyridin-4-yl-methoxy; R 3 represents hydrogen, alkyl, mono- or di-alkylamino, trifluoromethoxy or trifluoromethyl; in the case X represents CR 4, R 3 in addition represents halogen; and in the case A represents -CH2-CH2- or -CH2NH-, R3 in addition represents alkoxy; X represents N or CR 4; R 4 represents hydrogen, alkyl, alkoxy or halogen; and R 5 represents methyl or ethyl; and optically pure enantiomers, mixtures of enantiomers such as racemates, diastereomers, mixtures of diastereomers, diastereomeric racemates, and mixtures of diastereomeric racemates, as well as salts and solvents of such compounds, and morphological forms.