{TAIL ~ Z3} represents the atoms necessary to complete a mono or bicyclic aromatic or heterocyclic ting system containing 5 to 10 ring atoms and C is in an ortho or para position relative to {HEAD ~ W} 
{ TAIL ~ Z3 } represents the atoms necessary to complete a mono or bicyclic aromatic or heterocyclic ting system containing 5 to 10 ring atoms and C is in an ortho or para position relative to { HEAD ~ W }
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD