The compound 5 wherein X and X1 are independently selected from {HEAD ~ the group} consisting of {TAIL ~ Cl}, CF3CO2, CH3CO2, CFH2CO2, 3CO, 2CO, 2CO, PhO, MeO, EtO, tosylate, mesylate, and trifluoromethanesulfonate 
consisting of
The compound 5 wherein X and X1 are independently selected from { HEAD ~ the group } consisting of { TAIL ~ Cl } , CF3CO2 , CH3CO2 , CFH2CO2 , 3CO , 2CO , 2CO , PhO , MeO , EtO , tosylate , mesylate , and trifluoromethanesulfonate
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL 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