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