| Autor: |
Dener, J. M., Fantauzzi, P. P., Kshirsagar, T. A., Kelly, D. E., Wolfe, A. B. |
| Zdroj: |
Organic Process Research & Development; July 2001, Vol. 5 Issue: 4 p445-449, 5p |
| Abstrakt: |
Convenient and reliable large-scale procedures for the protection of various amino acids with N-(9-fluorenylmethoxycarbonyl)oxysuccinimide (FMOC-OSu) are described. Commercially available 4-aminomethylbenzoic acid and trans-4-(aminomethyl)cyclohexanecarboxylic acid were converted into their corresponding FMOC-derivatives in excellent yields without the need for an extractive workup. In addition, FMOC-cis-β-amino acids were also prepared, employing a [2 + 2]-cycloaddition strategy between a cyclic olefin and N-chlorosulfonyl isocyanate (CSI). The resulting N-chlorosulfonyl β-lactams were reduced to the parent β-lactams with sodium sulfite and then converted to the cis-β-amino acid hydrochlorides by exposure to aqueous hydrochloric acid. The resulting cis-β-amino acids were converted to their FMOC-derivatives under conditions similar to those developed for the commercially available amino acids. Differences in the conditions employed between these β-amino acids and the commercial derivatives were observed, primarily in the nature of the base required for the reaction. A possible rationale for the differences in behavior is described. These FMOC-amino acid derivatives are valuable intermediates for the solid-phase synthesis of combinatorial libraries. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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