Synthesis of 4'-N-CBZ-pradimic acid from pradimicin A
The sterically hindered alanine-amide bond of pradimicin A (PRM A, 1) was successfully cleaved via less hindered amide (11) by treatment with NOBF4 in eight steps to afford practical yield of 4'-N-Cbz-pradimic acid (13), which is a useful intermediate for the synthesis of alanine-exchanged derivatives.