dc.contributor.author |
Garcias, Rafael C.
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dc.contributor.author |
Coll, Miguel
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dc.contributor.author |
Donoso Pardo, Josefa Laurentina
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dc.contributor.author |
Muñoz Izquierdo, Francisco
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dc.date.accessioned |
2018-10-26T13:11:14Z |
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dc.identifier.uri |
http://hdl.handle.net/11201/148297 |
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dc.description.abstract |
[eng] The chemical behaviour of the penicillin nucleus towards nucleophilic attack by two thiols of disparate basicity such as 2-mercaptoethanol (1) and 2-mercaptoethylamine (2) was studied using density functional theory computations at the B3LYP/6-31+G* level. The crucial role of the intramolecular bond in the beta-lactam nitrogen was examined. Based on the energy values obtained, the formation of the tetrahedral intermediate (T in Scheme 1) is the rate-determining step of the process. The energies of activation for the process suggest general acid catalysis in 2 as a result of the presence of an effective proton donor group in b in the starting thiolate. This reduces the energy of formation of the tetrahedral intermediate from 12.04 kcal/mol for 1 to 4.51 kcal/mol for 2 <br> which possesses a more acidic group. This disparate behaviour is consistent with the experimental rate constant for the degradation of benzyl-penicillin in the presence of 2 [k1(2) = 1.3 · 10-1 mol-1 dm3 s-1], which is roughly two orders of magnitude higher than for other thiols of similar basic strength. |
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dc.format |
application/pdf |
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dc.relation.isformatof |
Versió postprint del document publicat a: https://doi.org/10.1016/j.theochem.2006.07.001 |
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dc.relation.ispartof |
Journal of Molecular Structure-Theochem, 2006, vol. 773, p. 29-34 |
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dc.subject.classification |
54 - Química |
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dc.subject.other |
54 - Chemistry. Crystallography. Mineralogy |
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dc.title |
Density functional theory study of the thiolysis reaction in penicillins |
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dc.type |
info:eu-repo/semantics/article |
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dc.type |
info:eu-repo/semantics/acceptedVersion |
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dc.date.updated |
2018-10-26T13:11:14Z |
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dc.date.embargoEndDate |
info:eu-repo/date/embargoEnd/2075-01-01 |
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dc.embargo |
2075-01-01 |
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dc.rights.accessRights |
info:eu-repo/semantics/embargoedAccess |
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dc.identifier.doi |
https://doi.org/10.1016/j.theochem.2006.07.001 |
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