Synthesis of hydrazinopeptides using solid-phase N-electrophilic amination:: extension to the Fmoc/tert-butyl strategy and chemistry of the N-N bond in strong acid media

The synthesis of hydrazinopeptides using solid-phase N-electrophilic amination was extended to the Fmoc/tert-butyl strategy. Both Boc/benzyl and Fmoc/tert-butyl strategies led to the isolation of by-products arising from the partial instability of the N-N bond during the final cleavage and deprotection step. Two paths of decomposition have been shown: the cleavage of the N-N bond leading to the regeneration of the amine and a Hofmann-type elimination yielding original dianisyl adducts. Our data suggest that the Fmoc/tert-butyl strategy is better suited for the synthesis of hydrazinopeptides.