{HEAD ~ The reaction step} can be conducted in {TAIL ~ the presence} of an organic solvent and a base 
conducted in
{ HEAD ~ The reaction step } can be conducted in { TAIL ~ the presence } of an organic solvent and a base
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH