N-Silylimine of Trifluoropyruvate in the Asymmetric Synthesis of Trifluoroalanine Derivatives
Aim. To develop a preparative method for the synthesis of N-trimethylsilylimine of trifluoropyruvate, and study its interaction with acetone under organocatalytic conditions. Results and discussion. A simple preparative approach to the first representative of N-silylimines of trifluoropyruvate was...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
National University of Pharmacy (Kharkiv, Ukraine)
2023-06-01
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| Series: | Журнал органічної та фармацевтичної хімії |
| Subjects: | |
| Online Access: | https://ophcj.nuph.edu.ua/article/view/284819 |
| Summary: | Aim. To develop a preparative method for the synthesis of N-trimethylsilylimine of trifluoropyruvate, and study its interaction with acetone under organocatalytic conditions.
Results and discussion. A simple preparative approach to the first representative of N-silylimines of trifluoropyruvate was developed based on the interaction of triphenylphosphinimide and trifluoropyruvic acid methyl ester by the aza-Wittig reaction. It was found that the addition of acetone to N-silylimine occurred in the presence of L- or D-proline and led to the formation of enantiomerically enriched α-amino-γ-oxocarboxylates. The hydrolysis of the ester function resulted in (R)-α-trifluoromethyl aminocarboxylic acid, and the cyclocondensation with isocyanates or 2,5-dimethoxytetrahydrofuran yielded nitrogen-containing heterocycles containing pyrimidine or pyrrolizine nuclei.
Experimental part. The synthetic procedures for the N-silylimine of trifluoropyruvate and its reaction with acetone are provided, along with the transformations of obtained α-amino-γ-oxocarboxylates (hydrolysis, cyclocondensations with isocyanates and 2,5-dimethoxytetrahydrofuran). The structures of the compounds synthesized were proven by 1H, 13C, 19F NMR spectroscopy methods, as well as by the elemental analysis.
Conclusions. A convenient method for the synthesis of N-silylimine of trifluoropyruvate has been developed. Using the example of the Mannich reaction with acetone, it has been demonstrated that N-silylimine of trifluoropyruvate is a convenient substrate for the synthesis of optically active 3,3,3-trifluoroalanine derivatives. |
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| ISSN: | 2308-8303 2518-1548 |