{HEAD ~ Suitable 4 2 piperazinones} include 4 2 piperazinone, 4 1 methyl 2 piperazinone, 4 3 methyl 2 piperazinone, 4 5 methyl 2 piperazinone, 3 ethyl 4 2 piperazinone, {TAIL ~ 3 ethyl 4 2 piperazinone}, 6 ethyl 4 2 piperazinone, 4 5,6 dimethyl 2 piperazinone, 1 ethyl 4 2 piperazinone, 4 3 phenyl 2 piperazinone, 1,4 bis 2 piperazinone, 4 2 piperazinone, 4 2 piperazinone and 4 6 methyl 2 piperazinone 
{ HEAD ~ Suitable 4 2 piperazinones } include 4 2 piperazinone , 4 1 methyl 2 piperazinone , 4 3 methyl 2 piperazinone , 4 5 methyl 2 piperazinone , 3 ethyl 4 2 piperazinone , { TAIL ~ 3 ethyl 4 2 piperazinone } , 6 ethyl 4 2 piperazinone , 4 5,6 dimethyl 2 piperazinone , 1 ethyl 4 2 piperazinone , 4 3 phenyl 2 piperazinone , 1,4 bis 2 piperazinone , 4 2 piperazinone , 4 2 piperazinone and 4 6 methyl 2 piperazinone
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