The next approach, by scientists at Beecham Research Laboratories (BRL), was to produce p‐aminobenzylpenicillin since its side chain could be modified later when required. Broth fermentation was again the method used, but in the absence of sufficient side chain precursors the resulting molecule, 6‐aminopenicillanic acid (6‐APA) identified in1957, was without a side chain. 6‐APA was used to produce synthetic β‐lactams, notably the β‐lactamase stable methicillin, launched in 1960