Dipyridylamine-acetamide (Dpaa): A primary amine protecting group orthogonally cleavable under acidic conditions in the presence of t-butyloxycarbonyl (Boc) and t-butylester

We show that dipyridylamine-acetamide (Dpaa), can be cleaved under mild acidic conditions (30% formic acid in dichloromethane). The release of the amine function is orthogonal to other acid-labile protecting groups. Calculations suggest that the ease of Dpaa cleavage relies on activation of the carbonyl function by the protonated dipyridylamine nitrogen and activation of a water molecule by a hydrogen-bond network.