Patent ID: 8524909

Claim:
A compound of formula I wherein R 1 and R 2 are each independently hydrogen, (CR 2 ) o -cycloalkyl optionally substituted by lower alkyl or hydroxy, or are lower alkyl or heterocycloalkyl, o is 0 or 1; and each R is the same or different and is hydrogen or lower alkyl; or R 1 and R 2 together with the N atom to which they are attached form a heterocycloalkyl group, selected from the group consisting of pyrrolidinyl, piperidinyl, 3-aza-bicyclo[3.1.0]hex-3-yl and 2-aza-bicyclo[3.1.0]hex-2-yl, each of which is optionally substituted by hydroxy; R 3 is S-lower alkyl, lower alkyl, lower alkoxy or cycloalkyl; R 3′ is hydrogen, lower alkyl substituted by halogen, lower alkyl or lower alkoxy; R 4 is lower alkyl substituted by halogen, lower alkyl or lower alkoxy; X is —O— or —CH 2 —; and X′ is —O— or —CH 2 —; with the proviso that one of X or X′ is always —O— and the other is —CH 2 —; or a pharmaceutically acceptable acid addition salt, racemic mixture, corresponding enantiomer or optical isomer thereof.