| 摘要 |
Disclosed are compounds of the formula <IMAGE> (I) wherein A represents the divalent radical -S-CR4=CR5- in which R4 and R5 independently represent hydrogen or lower alkyl; R1 represents hydrogen, lower alkyl or aryl-lower alkyl; R2 represents hydrogen, lower alkyl or aryl-lower alkyl; or R1 and R2 combined represent alkylene of 4 to 6 carbon atoms; R3 represents hydrogen or lower alkyl; an S-oxide thereof; or a pharmaceutically acceptable salt thereof; which are useful as presynaptic dopamine receptor agonists for the treatment of central nervous system disorders; processes for preparing same; and pharmaceutical compositions comprising said compounds. |
