Structure variations are done based on the activity tests. Especially, the modification of the α,β-unsaturated carbonyl system is in the focus in order to get compounds with better activity and selectivity.
The selection of the rests R' and R'' allows for a control on the electronic and steric properties in order to gain activity increase and activity loss. With continuous evaluation of the synthesized derivatives a sustained examination of activity is achieved which will lead to a structural optimization of potential drug candidates.