R8 is H, OH, alkoxy, phenoxy, benzyloxy, ##STR18## NR4 R5, lower alkyl, phenyl or R3 phenyl; {HEAD ~ R9} is O , CH2 , {TAIL ~ NH} or N  
is
R8 is H , OH , alkoxy , phenoxy , benzyloxy , # # STR18 # # NR4 R5 , lower alkyl , phenyl or R3 phenyl ; { HEAD ~ R9 } is O , CH2 , { TAIL ~ NH } or N
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 REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH