tert-butyl 4-(1,2-diphenylethyl)piperazine-1-carboxylate

tert-butyl 4-((1-methyl-1H-imidazol-2-yl)methyl)piperazine-1-carboxylate

tert-butyl 4-(4-fluorobenzoyl)piperazine-1-carboxylate

tert-butyl 4-(3-(dimethylamino)-3-oxopropyl)piperazine-1-carboxylate