Description Quasi-orthogonally-protected Glu derivative.The 2-PhiPr group can be removed selectively in the presence of tBu-based protecting groups by treatment with 1% TFA in DCM [1], making this derivative an extremely useful tool for the preparation of cyclic peptides by Fmoc SPPS [2] or for library synthesis. For the on-resin synthesis of side-chain to side-chain lactam bridged peptides, the combination of Lys(Mtt) and Glu(O-2-PhiPr) is particularly advantageous since both side-chains can be simultaneously unmasked in a single step.The product number for this product was previously 04-12-1199..