| abstract |
The present invention relates to a compound of formula I n nwhereinn R 1 , R 2 , X, Ar 1 and Ar 2 are as defined herein and to pharmaceutically acceptable acid addition salts, to a racemic mixtures, or to their corresponding enantiomers and/or optical isomers thereof. Compounds of the invention are good inhibitors of the glycine transporter 1 (GlyT-1), and have a good selectivity to glycine transporter 2 (GlyT-2) inhibitors. |