Ampicillin remains the penicillin of choice for many infections because of its oral activity and good potency against
Gram-negative bacteria. A number of
prodrugs have been examined in attempts to improve upon the
pharmacodynamic characteristics, and one of these is talampicillin. One synthesis involved protecting the primary amino group of
ampicillin (
1) as the enamine with
ethyl acetoacetate (
2). THis was then esterified by reaction with 3-bromopthalide (
3), and the enamine was carefully hydrolyzed with dilute HCl in acetonitrile to produce talampicillin (
4). ==References==