Lactonyl esters of ampicillin and other penicillins have been synthesized as prodrugs designed to improve the oral absorption of the parent penicillins. In general, the esters hydrolyzed rapidly in the presence of tissues including blood and certain of the esters were better absorbed than the parent penicillin. The phthalidyl ester of ampicillin [talampicillin (British Pharmacopoeia approved name), BRL 89881 was selected for extended studies. ...
![potassium,(2S,5R,6R)-6-[[2-[[(E)-4-methoxy-4-oxobut-2-en-2-yl]amino]-2-phenylacetyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate Structure](https://image.chemsrc.com/caspic/060/40126-27-0.png)
![4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylicacid, 6-[[(2R)-2-amino-2-phenylacetyl]amino]-3,3-dimethyl-7-oxo-,1,3-dihydro-3-oxo-1-isobenzofuranyl ester, (2S,5R,6R)- Structure](https://image.chemsrc.com/caspic/262/47747-56-8.png)