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