The inspiration is X_0770, one of the covalent fragments. I based these designs on a simple 3-step synthetic route with commercially available boc-protected piperazines. First step is nucleophilic substitution with 1-(bromomethyl)-3-chlorobenzene, then deprotection, and then amidation with 2-chloroacetyl chloride. I docked them using the constrained scaffold of X_0770, and chose that seem compatible. Also, I predict that the ones with the substitution next to the chloroacetamide will have reduced electrophile reactivity due to steric hindrance. If you have any questions, feel free to email me.