Computational elucidation of the reaction mechanism for synthesis of pyrrolidinedione derivatives via Nef-type rearrangement – cyclization reaction
| Autor: | Rositca D. Nikolova, Eleonora D. Ilieva, Georgi N. Vayssilov, Galina P. Petrova |
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| Rok vydání: | 2018 |
| Předmět: |
Reaction mechanism
Nitromethane 010405 organic chemistry General Chemical Engineering General Chemistry 010402 general chemistry 01 natural sciences Tautomer Medicinal chemistry Pyrrolidine Transition state 0104 chemical sciences chemistry.chemical_compound Deprotonation chemistry Michael reaction Methylene |
| Zdroj: | RSC Advances |
| ISSN: | 2046-2069 |
| DOI: | 10.1039/c7ra11908a |
| Popis: | This paper reports a quantum chemical study of all stages of a one-pot synthesis of pyrrolidinedione derivatives from nitromethane and coumarin, which includes Michael addition, migration of an oxygen atom (Nef-type rearrangement), and cyclization to a pyrrolidine ring. The energy barrier of deprotonated nitromethane addition to coumarin is 21.7 kJ mol−1, while the barrier of proton transfer from the methylene to the nitro group in the nitromethyl group is notably higher, 197.8 kJ mol−1. The second stage of the reaction, migration of an oxygen atom within the nitromethyl group, occurs with lowest energy barrier, 142.4 kJ mol−1, when it is assisted by an additional water molecule. The last stage – cyclization, passes with a very low energy barrier of 11.9 kJ mol−1 but the tautomerization of the nitrosohydroxymethyl group to the hydroxy-N-hydroxyiminomethyl, necessary for the process, has an energy barrier of 178.4 kJ mol−1. Analogous calculations for the same process with the ethyl ester of 3-coumarin-carboxylic acid as substrate show that the relative energies of the intermediates and transition states are by at most 10–16 kJ mol−1 more stable than the corresponding structures with coumarin. |
| Databáze: | OpenAIRE |
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