A compound of the formula (I), or a pharmaceutically acceptable salt thereof, ** Formula ** a tautomeric form thereof in which: R1 is alkyl, Cl, F or Br； R2 is H or F； R3 is selected from H and alkyl； R4 is selected from C (O) R6； R5 is H； or R4 and R5 are linked to form a heterocyclic group that is optionally substituted with one or more R10 groups； R6 is selected from R7, OR7 and NR8R9； R7, R8 and R9 are each independently selected from alkyl, cycloalkyl, aralkyl, cycloalkenyl, heterocyclyl and aryl, each of which is optionally substituted with one or more R10 groups； Each R10 is independently selected from halogen, OH, CN, COO-alkyl, aralkyl, SO2-alkyl, SO2-aryl COOH, CO alkyl, CO-aryl, NH2, NH-alkyl, N (alkyl) 2, CF3, alkyl and alkoxy； X and Z are each independently CR11, and Y is selected from CR11 and N； R11 is H or F； for use in the treatment of a disorder related to stress due to poor protein folding and, in particular, with the accumulation of misfolded proteins, chosen from Charcot Marie Tooth neuropathy； severe Dejerine-Sottas syndrome, retinal diseases, preferably retinitis pigmentosa, ciliopathies of the retina, macular degeneration or diabetic retinopathy and ALS.Un compuesto de la fórmula (I), o una sal farmacéuticamente aceptable del mismo,**Fórmula** una forma tautomérica del mismo en el que: R1 es alquilo, Cl, F o Br； R2 es H o F； R3 está seleccionado de entre H y alquilo； R4 está seleccionado de entre C(O)R6； R5 es H； o R4 y R5 están unidos para formar un grupo heterocíclico que opcionalmente se sustituye con uno o más grupos R10； R6 está seleccionado de entre R7, OR7 y NR8R9； R7, R8 y R9 están cada uno independientemente seleccionados de entre alquilo, cicloalquilo, aralquilo, cicloalquenilo, heterociclilo y arilo, cada uno de los cuales está sustituido opcionalmente con uno o más grupos R10； cada R10 está independientemente seleccionado de entre halógeno, OH, CN, COO-alquilo, aralquilo, SO2-alquilo, SO2-arilo COOH, CO alquilo, CO-arilo, NH2, NH-
