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