Poly (ethylene glycol)(PEG) was derivatized with a number of acid-cleavable and photocleavable anchoring groups in order to test the applicability of these derivatives as supports in liquid-phase peptide synthesis. PEG was subjected to rapid and quantitative derivatization with aliphatic and aromatic isocyanates to give the corresponding urethanes. These PEG derivatives were tested for their stability under various conditions employed in ...