Class of histone deacetylase inhibitors

A compound of formula (I)

• wherein:
• Q is a bond, CH2, NR5 or oxygen;
• X is CH or nitrogen;
• Y is a bond, CH2, oxygen or NR6;
• Z is CH or nitrogen;
• R1, R2 are, independently, hydrogen or C1-C6 alkyl;
• R3, R4 are, independently, hydrogen, halogen, C1-C6 alkyl, C1-C6 alkoxy, C1-C6haloalkyl or C1-C6 haloalkoxy;
• R5 is hydrogen, C1-C6 alkyl, (CO)R7, phenyl or benzyl;
• R6 is hydrogen, C1-C6 alkyl or benzyl;
• R7 is hydrogen, C1-C6 alkyl, phenyl, benzyl, OR8 or NR9R10;
• R8 is C2-C6 alkyl;
• R9 is hydrogen, C1-C6 alkyl, phenyl or benzyl;
• R10 is hydrogen, C1-C6 alkyl or benzyl;
• and the pharmaceutically acceptable salts thereof.