Conjugation of Oligonucleotides to Peptide Aldehydes via a pH-Responsive -Methoxyoxazolidine Linker.

The formation of -methoxyoxazolidines in the preparation of oligonucleotide-peptide conjugates was evaluated. The reaction occurred between unprotected 2'--(methoxy)amino-modified oligonucleotides and peptide aldehydes in reasonable yields when isolated. The reaction is reversible under slightly acidic conditions, and it is pH-responsive.