{HEAD ~ R7} is OH, lower alkyl, phenyl, benzyl, R3 phenyl or {TAIL ~ R3 benzyl} 
is
{ HEAD ~ R7 } is OH , lower alkyl , phenyl , benzyl , R3 phenyl or { TAIL ~ R3 benzyl }
HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL