| abstract |
Disclosed is a compound of formula I, a stereoisomer thereof, a cis-trans-isomer thereof, a tautomer thereof, or a mixture thereof, or a pharmaceutically acceptable salt thereof, a solvate thereof or a prodrug thereof, n n n n n n n n n n n n wherein R 1 , R 2 , R 3 and R 4 are each as defined in the present application. |