Patent ID: 7396897

Claim:
A compound of formula (II) wherein: n is 3 or 4, P is different from P′, and P and P′ are 0 or 1, wherein when P′ is 0, then the adjacent —NH group is engaged in an N-ε polymerization and when P is 0, then the adjacent —NH group is engaged in an N-α polymerization; and when P or P′ is 1, then R or R′ is A′-SH, wherein A′ is chosen from compounds of formula: wherein R 1 , R 2 , R 3 , and R 4 , which may be identical or different, are chosen from hydrogen, and —COOH, —OH, —NH 2 , alkyl(C-1 to C-8)amino, acyl(C-1 to C-8)amino, acyl(C-1 to C-8)oxy, alkyl(C-1 to C-8)oxycarbonylamino, alkyl(C-1 to C-8)aminocarbonyloxy, halo, and alkyl(C-1 to C-8)aminocarbonyl radicals; wherein q ranges from 1 to 36; wherein R or R′ may also be chosen from hydrogen, and salts thereof, and and salts thereof; and m ranges from 3 to 10,000.