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Benzylpenicillin cleavage with polyelectrolytes
Author(s) -
Arcelli Antonio,
Cecchi Romina,
Porzi Gianni,
Sandri Monica
Publication year - 2005
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.877
Subject(s) - aminolysis , chemistry , polyelectrolyte , nucleophile , polymer chemistry , hydrolysis , catalysis , substrate (aquarium) , amine gas treating , reaction rate constant , medicinal chemistry , organic chemistry , kinetics , polymer , oceanography , physics , quantum mechanics , geology
Kinetic studies of the aminolysis of benzylpenicillin (BP) in poly(ethylenimine) (PEI) showed a complicated rate behaviour owing to the strong substrate–polyelectrolyte interaction. The results were interpreted by the formation of an unreactive and reactive complex which is converted into the poly(ethylenimine)penicilloylamide. In the presence of KCl the PEI behaves as a simple amine and the second‐order rate constants ( k N ) of the nucleophilic attack on β‐lactam were calculated at various pH values. The Brønsted β value is consistent with a stepwise mechanism in which the rate‐determining step is the T ± intermediate decomposition in absence of general acid–base catalysis. The PEI reveals its catalytic ability not only by binding the substrate to the polymer, but also by increasing the reactivity of the reactive complex. A negligible effect on the alkaline hydrolysis of BP was found in the presence of poly(diallyldimethylammonium) chloride (PDDA). A parallel between PEI and human serum albumin (HSA) in the BP aminolysis is proposed. Copyright © 2004 John Wiley & Sons, Ltd.