Rate, increased with neighboring group participation

Fig. 5.7. The acid-catalyzed hydrolysis of penicillins involves first the formation of an acylium ion (5.22), which, by reacting with H20, yields penicil-loic acids 5.24 (Pathway b). The participation of a neighboring 6-acylamido group increases the rate of hydrolysis. During this intramolecular reaction (Pathway a), oxazolylthiazolidines (5.23) are formed and then give rise to the degradation products penicilloic acids 5.24, penicillenic acids 5.25,...

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