The present invention relates to a compound of formula (I), or a tautomer and/or a pharmaceutically acceptable salt thereof, wherein: R 1 is alkyl, Cl, F or Br； R 2 is H or F； R 3 is selected from H and alkyl； R 4 is selected from H and C(O)R 6 ； R 5 is H； or R 4 and R 5 are linked to form a heterocyclic group which is optionally substituted with one or more R 10 groups；R 6 is selected from R 7 , OR 7 and NR 8 R 9 ； R 7 , R 8 and R 9 are each independently selected from alkyl, cycloalkyl, aralkyl, cycloalkenyl, heterocyclyl and aryl, each of which is optionally substituted with one or more R 10 groups； each R 10 is independently selected from halogen, OH, CN, NO 2 , COO-alkyl, aralkyl, SO 2 -alkyl SO 2 -aryl, COOH, CO-alkyl, CO-aryl, NH 2 , NH-alkyl, N(alkyl) 2 , CF 3 , alkyl and alkoxy； X and Z are each independently CR 11 , and Y is selected from CR 11 and N； and R 11 is H or F； for use in treating a disorder associated with protein misfolding stress and in particular associated with accumulation of misfolded proteins.
