The present invention relates to a compound of formula (IA), wherein G1 is lower alkyl； lower alkyl substituted by one or more halogens； cycloalkyl； tetrahydropyran-4-yl； phenethyl； phenethyl substituted by one or more halogens； phenoxymethyl； phenoxymethyl substituted by one or more halogens； benzyloxyethyl； benzyloxy-ethyl substituted by one or more halogens； or is &mdash；NR2R3； R2 is hydrogen or lower alkyl； R3 is lower alkyl； tetrahydropyran-4-yl； &mdash；CH2-cycloalkyl； or cycloalkyl optionally substituted by lower alkyl substituted by one or more halogens； or R2 and R3 form together with the N-atom to which they are attached a heterocycloalkyl group with 4 or 5 carbon atoms, which is optionally substituted by one or more substituents selected from halogen； or lower alkyl substituted by one or more halogens； X is &mdash；CH2&mdash；or &mdash；(CH2)2&mdash；； Ar is phenyl or pyridinyl； R4 is halogen； lower alkyl； lower alkyl substituted by one or more halogens； or lower alkoxy； n is 1 or 2； or to a pharmaceutically active salt thereof, to a stereoisomeric form, including an individual diastereoisomer or enantiomer of the compound of formula (IA) as well as to a racemic or non-racemic mixture thereof. The present invention also relates to the use of a compound of formula (IA) for treating certain neurodegenerative disorders characterized by cytotoxic TAU misfolding and/or aggregation.
