No abstract

The final step of the semisynthetic route to paclitaxel involves cleavage of the triethylsilyl (TES) protecting group from the C-7 hydroxyl group. Paclitaxel is an extremely complex molecule, and standard deprotection conditions led to formation of several impurities. Trifluoroacetic acid in aqueous acetic acid was found to be very effective in the cleavage of the TES group without compromising the quality of the product.

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A Chemoselective, Acid-Mediated Conversion of Amide Acetal to Oxazole: The Key Step in the Synthesis of Cardiovascular Drug, Ifetroban Sodium.-An optimized route to the precursor (VIII) of the cardiovascular drug ifetroban sodium is reported. The strategy involves a high-throughput and high-yielding sequence for the preparation of the amide acetal (IV) and cyclization of the adduct (VI) to the oxazoline as key step. -(SWAMINATHAN, S.; SINGH, A. K.; LI, W.-S.; VENIT, J. J.; NATALIE, K.