The compounds of this invention wherein {HEAD ~ R} is CO2 H can be attached to a biomolecule through {TAIL ~ an amine group} or a hydroxyl group on the latter 
The compounds of this invention wherein { HEAD ~ R } is CO2 H can be attached to a biomolecule through { TAIL ~ an amine group } or a hydroxyl group on the latter
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH