A process for the production of leather and for suitable compounds

A process for the production of leather by contacting pretreated animal hides with at least one compound which has at least one group of formula I, where the variables are defined as follows: Ar X is an electron withdrawing group or hydrogen, Y a bivalent functional group or a single bond or a C W a radical which is derived from a compound which acts on hydrophobicizing leather, greasy or tanning, B selected from -C (R R R Q out can be eliminated under aqueous alkaline conditions groups.