A Search For Phenolic Protection in Virginiamycin S

In order to be able to mask the hydroxyl grouping of the pipecolic acid residue in Virginiamycin during alkaline (NaOH) and acidic (Tfa) break‐down procedures and to use peptidic fragments coming thereof for further reconstitution by classical peptide synthesis procedures, we have investigated several candidates for protection/deprotection. Thus the phenacyl derivatives (4 & 5), the allyloxycarbonyl derivative (6), the trichloroethyloxycarbonyl derivatives (8 & 9) and the 2,4‐dinitrophenyl derivative (10) have been prepared. Among these none were stable in aqueous basic conditions. The Alloc‐ (6) the Troc (8) and Dnp‐derivative (10) may have some applications under acidic conditions.