The availability of APA,* the penicillin nucleus, l has made possible the preparation of new penicillins not previously available by fermentation procedures. The treatment of APA with the acid chloride or anhydride of the appropriate acid has been used to prepare such penicillins. 2 In order to prepare for biological testing as wide a range of new penicillins as possible, alternate methods for the condensation of carboxylic acids with APA were ...
![sodium,(2S,5R,6R)-6-amino-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate Structure](https://image.chemsrc.com/caspic/115/1203-85-6.png)
