(A) HPLC chromatogram of 2. (B) HPLC chromatogram of 2 subsequent to reduction, in an argon atmosphere, with excess NaBH4 for 1h in H2O containing 20% ethanol by volume. (C) HPLC chromatogram of the material in panel (B) after, quenching with acetic acid, adjusting to pH 7.4 with phosphate buffer and bubbling under a stream of O2 for 10 min. Chromatograms D-F are a similar sequence with 3, but the reduction time was 40 min. For further details see Experimental and Results.