The 1 benzotriazolylcarbonate ester can then be reacted directly with {TAIL ~ a biologically active agent} to form a biologically active polymer conjugate or reacted with an amino acid, such as lysine, to form {HEAD ~ an amino acid derivative} 
The 1 benzotriazolylcarbonate ester can then be reacted directly with { TAIL ~ a biologically active agent } to form a biologically active polymer conjugate or reacted with an amino acid , such as lysine , to form { HEAD ~ an amino acid derivative }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL 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 HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD