Davis, Andrew M., Layland, Nicola J., Page, Michael I., Martin, Frances and O'Ferrall, Rory More (1991) Thiazolidine ring opening in penicillin derivatives. Part 2. Enamine formation. Journal of the Chemical Society, Perkin Transactions 2 (8). pp. 1225-1229. ISSN 1472-779XMetadata only available from this repository.
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 build-up 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.
|Subjects:||Q Science > Q Science (General)|
Q Science > QD Chemistry
|Schools:||School of Applied Sciences|
|Depositing User:||Sharon Beastall|
|Date Deposited:||06 Nov 2009 09:41|
|Last Modified:||06 Nov 2009 09:41|
Repository Staff Only: item control page