The present invention relates to compounds as inhibitors of enzymes having histone deacetylase activity, to the processes for the preparation of those compounds, and to their use for the treatment of diseases which are associated with hypoacetylation of histones and/or other molecules, or in which induction of hyperacetylation has a beneficial effect for example by inhibition of proliferation and/or induction of differentiation and/or induction of apoptosis in transformed cells, such as cancer. Furthermore, the compounds are useful for the treatment of other proliferative diseases, for therapy or prophylaxis of conditions associated with abnormal gene expression.