An isolable acyclic hemiacetal of ansamitocin P‐3 |
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Authors: | Nathaniel L Segraves Derrick Yazzie Alan J Deese |
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Institution: | Department of Small Molecule Pharmaceutical Sciences, Genentech Inc., , South San Francisco, CA, 94080 USA |
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Abstract: | During impurity analysis of maytansinol (2), produced from the reduction of ansamitocin P‐3 (AP‐3, 1), a surprisingly stable acyclic hemiacetal (4) was isolated. A combination of 1D and 2D NMR experiments, along with liquid chromatography–mass spectrometry data was used to confirm the structure. Comparison of NMR data to the previously reported bridged acetal (3), a by‐product of AP‐3 reduction, supports reassignment of the latter to the former. Additionally, ROESY data, in conjunction with minimum energy calculations, support intramolecular hydrogen bonding that is involved in stabilizing the hemiacetal. This report adds another example to the very short list of isolable acyclic hemiacetals. Copyright © 2012 John Wiley & Sons, Ltd. |
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Keywords: | NMR 1H 13C maytansinoid ansamitocin stable acyclic hemiacetal AP‐3 purification |
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