{HEAD ~ Heterosubstituted hydrocarbyl groups} have one or more hydrogen atoms substituted by a heteroatom, even including one carbon species such as cyano and {TAIL ~ carboxy} 
{ HEAD ~ Heterosubstituted hydrocarbyl groups } have one or more hydrogen atoms substituted by a heteroatom , even including one carbon species such as cyano and { TAIL ~ carboxy }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL