6-APA
6-APA is an abbreviation used for the name of the chemical compound -6-aminopenicillanic acid. In 1958, Beecham scientists found a way to obtain 6-APA from penicillin. Other β-lactam antibiotics could then be synthesized by attaching various side-chains to the nucleus. The other antibiotics are used in place of penicillin G or penicillin V.
The reason why this was achieved so many years after the commercial development of penicillin by Howard Florey and Ernst Chain lies in the fact that penicillin itself is very susceptible to hydrolysis, so direct replacement of the side-chain was not a practical route to other β-lactam antibiotics.
