Synthesis 2023; 55(16): 2460-2472
DOI: 10.1055/s-0042-1751447
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Use of the N–O Bonds in N-Mesyloxyamides and N-Mesyloxyimides To Gain Access to 5-Alkoxy-3,4-dialkyloxazol-2-ones and 3-Hetero-Substituted Succinimides: A Combined Experimental and Theoretical Study

Lucca Pfitzer
a   Universität Stuttgart, Institut für Organische Chemie, Pfaffenwaldring 55, 70569 Stuttgart, Germany
,
Juliane Heitkämper
b   Universität Stuttgart, Institut für Theoretische Chemie, Pfaffenwaldring 55, 70569 Stuttgart, Germany
,
b   Universität Stuttgart, Institut für Theoretische Chemie, Pfaffenwaldring 55, 70569 Stuttgart, Germany
,
René Peters
a   Universität Stuttgart, Institut für Organische Chemie, Pfaffenwaldring 55, 70569 Stuttgart, Germany
› Author Affiliations
J.H. acknowledges financial support in the form of a Ph.D. scholarship from the Studienstiftung des Deutschen Volkes (German National Academic Foundation). We thank the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) for supporting this work by funding EXC 2075-390740016 under Germany’s Excellence Strategy. The authors acknowledge support by the Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg through bwHPC and the DFG through grant no. INST 40/575-1 FUGG (JUSTUS 2 cluster).


Abstract

The reactivity of N-mesyloxyamides and -imides with bases was studied based on the initial hypothesis of a possible [3,3]-rearrangement. While the intended α-sulfonyloxylation method could not be developed, the formation of valuable N-containing heterocyclic products was found. Treating N-mesyloxyamides with triethylamine gave fully substituted oxazolone products, which are masked α-amino acid derivatives. The products were identified by a computational approach, which revealed that α-lactams are first formed from an initial enolate by an intramolecular nucleophilic substitution. As strained intermediates, they readily rearrange to the oxazolone products. With a cyclic N-mesyloxyimide, elimination to a maleimide was found. This might indicate that sulfonyloxylation has taken place, but the corresponding product probably underwent elimination. Nucleophiles were then added to trap this suspected intermediate by substitution of methanesulfonate. That way, quaternary α-nitrogen- and α-oxygen-substituted succinimides could be formed, which represent a pharmacologically important class that has received much attention for its value in drug design.

Supporting Information



Publication History

Received: 16 February 2023

Accepted after revision: 28 March 2023

Article published online:
11 May 2023

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