R7 represents H, {HEAD ~ C1} 4 alkyl or {TAIL ~ trifluoromethyl} 
R7 represents H , { HEAD ~ C1 } 4 alkyl or { TAIL ~ trifluoromethyl }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL