Norvaline derivative of the formula [I] or pharmaceutically acceptable salt thereof, method for preparing the same, pharmaceutical composition containing the same, and use of said compound for inhibiting transporting activity of glycine transporter type 2 (GlyT2).[wherein X is －CH2－, －O－, －S－ or single bond；Ar is optionally substituted aryl or lower cycloalkyl；n is 0 to 2；R1and R2are (i) each is hydrogen or lower alkyl；(ii) R1and R2are combined to form lower alkylene；or (iii) R1is hydrogen or lower alkyl and R2is combined with R4or R6to form lower alkylene；R3and R4are (i) each is hydrogen or lower alkyl；(ii) R3and R4are combined to form lower alkylene；or (iii) R3is hydrogen or lower alkyl and R4is combined with R2or R6to form lower alkylene；R isor －OR7；R5and R6are (i) each is optionally substituted lower alkyl, or hydrogen；(ii) R5and R6are combined to form aliphatic 5－ to 6－membered heterocyclic group；or (iii) R5is optionally substituted lower alkyl or hydrogen and R6is combined with R2or R4to form lower alkylene；R7is lower alkyl.本發明提供式[I]之正纈胺酸衍生物或其醫藥上可接受之鹽、製備上述化合物之方法、包含上述化合物之醫藥組成物、及上述化合物用於抑制第二型甘胺酸轉運子(GlyT2)之轉運活性之用途。[式中，X為－CH2－、－O－、－S－或單鍵；Ar為視需要經取代之芳基或低碳數環烷基；n為0至2；R1及R2係(i)各為氫或低碳數烷基；(ii)R1及R2組合形成低碳數伸烷基；或(iii)R1為氫或低碳數烷基且R2與R4或R6組合形成低碳數伸烷基；R3及R4係(i)各為氫或低碳數烷基；(ii)R3及R4組合形成低碳數伸烷基；或(iii)R3為氫或低碳數烷基且R4與R2或R6組合形成低碳數伸烷基；R為或－OR7；R5及R6係(i)各為視需要經取代之低碳數烷基或氫；(ii)R5及R6組合形成脂族5－至6－員雜環基；或(iii)R5為視需要經取代之低碳數烷基或氫且R6與R2或R4組合形成低碳數伸烷基；R7為低碳數烷基]。
