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