John C. Sheehan
Born Sep 23 1915 - Died Mar 21 1992
Displacement of the Thiazolidine Ring in Penicillin with the Formation of a Biologically Active Cephem System
Patent Number(s) 3,939,151
Sir Alexander Fleming's 1928 discovery of penicillin in bread mold was a tremendous breakthrough for medical science. Unfortunately, Fleming's process for harvesting the antibiotic took months to generate a small amount. During World War II, as demand for penicillin rose, researchers worked feverishly to synthesize the penicillin molecule. More than a thousand scientists in 39 U.S. labs became involved in the project. But when the war ended and the molecule still had not revealed its structure, the funds for research ended. From 1948 to 1957 only one laboratory of continued the research-John Sheehan's. In March of 1957, while a professor at the Massachusetts Institute of Technology, Sheehan announced the first rational total synthesis of natural penicillin. The next year he reported a general total synthesis of penicillins.
Sheehan's total synthesis of penicillin in the early 1950s paved the way for mass commercial production of the antibiotic. A wider range of penicillin derivatives has been discovered to treat a wider range of diseases. The variations of penicillin have advanced so much that there are variants to fit any specific medical problem.