P 2618 (OTTO) Pentafluorophenol, 99% Cas 771-61-9 - used as a precursor in both solution and solid-phase peptide synthesis. P 2618 (OTTO) Pentafluorophenol, 99% Cas 771-61-9 - used as a reactant to synthesize pentafluorophenyl formate which can be used as a formylating agent in organic synthesis.