Thiazolidine Ring Opening in Penicillin Derivatives. Part 2. Enamine Formation

Andrew M. Davis, Nicola J. Layland, Michael I. Page, Frances Martin, Rory More O’ferrall

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The alkaline hydrolysis of (3S,5R,6R)-methyl benzylpenicilloate, and the corresponding carboxamide and N-ethylamide, is accompanied by an absorbance increase at 285 nm. This is attributed to a competing elimination reaction across C6–C5 to open the thiazolidine ring and reversibly generate an enamine intermediate. Kinetic analysis and hydrolysis in D2O do not indicate a significant buildup of this intermediate during hydrolysis of the methyl ester. However, over the pH range 4–11 the rate of thiazolidine ring opening is competitive with hydrolysis of the ester function. The deuterium solvent kinetic isotope effect on the ring closure reaction is 7.5.

LanguageEnglish
Pages1225-1229
Number of pages5
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number8
DOIs
Publication statusPublished - Aug 1991

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Thiazolidines
Penicillins
Hydrolysis
Derivatives
Esters
Kinetics
Deuterium
Isotopes

Cite this

Davis, Andrew M. ; Layland, Nicola J. ; Page, Michael I. ; Martin, Frances ; O’ferrall, Rory More. / Thiazolidine Ring Opening in Penicillin Derivatives. Part 2. Enamine Formation. In: Journal of the Chemical Society, Perkin Transactions 2. 1991 ; No. 8. pp. 1225-1229.
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Thiazolidine Ring Opening in Penicillin Derivatives. Part 2. Enamine Formation. / Davis, Andrew M.; Layland, Nicola J.; Page, Michael I.; Martin, Frances; O’ferrall, Rory More.

In: Journal of the Chemical Society, Perkin Transactions 2, No. 8, 08.1991, p. 1225-1229.

Research output: Contribution to journalArticle

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