PERMANGANATE-OXIDATION OF PEPTIDES. I. THE OXIDATION OF PROLINE RESIDUE IN N-PROTECTED PROLINE TO PYROGLUTAMYL RESIDUE
The oxidation of N-protected proline and related compounds with permanganate was investigated. The proline residue in N-acyl-L-proline was readily oxidized in the presence of strong acid to pyroglutamyl residue, in a manner different from that of free proline. In the oxidation of Nδ-benzyloxycarbonyl-L-ornithine under the same conditions, the methylene group adjacent to the protected δ-amino nitrogen was also attacked.