6-APA ((+)-6-aminopenicillanic acid) is a chemical compound used as an intermediate in the synthesis of

β-lactam antibiotic β-lactam antibiotics (beta-lactam antibiotics) are antibiotics that contain a beta-lactam ring in their chemical structure. This includes penicillin derivatives (penams), cephalosporins and cephamycins (cephems), monobactams, carbapenems and c ...

s. The major commercial source of 6-APA is still natural

penicillin G Benzylpenicillin, also known as penicillin G (PenG) or BENPEN, and in military slang "Peanut Butter Shot" is an antibiotic used to treat a number of bacterial infections. This includes pneumonia, strep throat, syphilis, necrotizing enterocolitis ...

: the semi-synthetic penicillins derived from 6-APA are also referred to as penicillins and are considered part of the penicillin family of antibiotics. In 1958,

Beecham Beecham is a surname. Notable people with the surname include: * Audrey Beecham (1915–1989), poet and niece of the conductor * Betty Humby Beecham (1908–1958), British pianist and wife of the conductor * Earl Beecham (born 1965), American foo ...

scientists from

Brockham Brockham is a village and civil parish in the Mole Valley district of Surrey, England. It is approximately east of Dorking and west of Reigate. The village lies south of Box Hill, with the River Mole flowing west through the village. At the ...

Park,

Surrey Surrey () is a ceremonial and non-metropolitan county in South East England, bordering Greater London to the south west. Surrey has a large rural area, and several significant urban areas which form part of the Greater London Built-up Area. ...

, found a way to obtain 6-APA from

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from ''Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum using ...

. Other β-lactam antibiotics could then be synthesized by attaching various side-chains to the nucleus.F.P. Doyle, J.H.C. Nayler, G.N. Rolinson ''US Patent 2,941,995'', filed July 22, 1958, granted June 21, 1960. Recovery of solid 6-aminopenicillanic acid. The reason why this was achieved so many years after the commercial development of penicillin by

Howard Florey Howard Walter Florey, Baron Florey (24 September 189821 February 1968) was an Australian pharmacologist and pathologist who shared the Nobel Prize in Physiology or Medicine in 1945 with Sir Ernst Chain and Sir Alexander Fleming for his role in ...

and Ernst Chain lies in the fact that penicillin itself is very susceptible to

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

, so direct replacement of the side-chain was not a practical route to other β-lactam antibiotics.

References

Beta-lactam antibiotics Sulfur heterocycles Amines