Suppression of piperidine-mediated side product formation for Asp(OBut)-containing peptides by the use of N-(2-hydroxy-4-methoxybenzyl)(Hmb) backbone amide protection

Piperidine-mediated aspartimide and subsequent piperidide formation, during Fmoc-based synthesis of sensitive aspartyl (β-tert-butyl ester, OBut)-containing peptides, is completely suppressed by the use of Hmb protection of the aspartyl amide bond.