Polymer-Assisted Synthesis of Single and Fused Diketomorpholines
Language English Country United States Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
- Keywords
- bromoketone, diketomorpholine, morpholine, serine, solid-phase synthesis,
- MeSH
- Acylation MeSH
- Alkylation MeSH
- Cyclization MeSH
- Trifluoroacetic Acid chemistry MeSH
- Carboxylic Acids chemistry MeSH
- Molecular Structure MeSH
- Morpholines chemical synthesis MeSH
- Nitrobenzenes chemistry MeSH
- Oxazines chemistry MeSH
- Polymers chemistry MeSH
- Silanes chemistry MeSH
- Stereoisomerism MeSH
- Solid-Phase Synthesis Techniques methods MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- 4-nitrobenzenesulfonyl chloride MeSH Browser
- Trifluoroacetic Acid MeSH
- Carboxylic Acids MeSH
- Morpholines MeSH
- Nitrobenzenes MeSH
- Oxazines MeSH
- Polymers MeSH
- Silanes MeSH
- triethylsilane MeSH Browser
The synthesis of different diketomorpholines via N-acyl-3,4-dihydro-2 H-1,4-oxazine-3-carboxylic acids is reported in this article. The key intermediates were prepared using a convenient solid-phase synthesis starting from polymer-supported Ser( tBu)-OH. After subsequent sulfonylation with 4-nitrobenzenesulfonyl chloride (4-Nos-Cl), alkylation with an α-bromoketone, cleavage of the 4-Nos group and acylation with an α-halocarboxylic acids, acid-mediated cleavage from the resin yielded dihydrooxazine-3-carboxylic acids in high crude purities. Depending on the reaction conditions, exposure to base resulted in cyclization to either oxazino[3,4- c][1,4]oxazine-diones or 3-methylidenemorpholine-2,5-diones. Further reaction with triethylsilane-trifluoroacetic acid (TES/TFA) led to olefin reduction, in the case of oxazino[3,4- c][1,4]oxazine-dione with full control of the newly formed stereocenter.
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