Amino acid and peptide chemistry on silicones

Poly(dimethylsiloxanes), di-terminated with amino acids, were synthesized by employing the Diels-Alder reaction of cyclopentadiene- or furan-terminated poly(dimethylsiloxanes) with functional dienophiles including N-maleoyl-protected phenylalanine. The amino acid could be chain extended using conventional solution peptide coupling with DCC, DMAP and N-hydroxysuccinimide to give a dipeptide-terminated silicone. The molecular weight of the silicone component of the telechelic system could be increased by acid-catalyzed redistribution with octamethylcyclotetrasiloxane (D₄).