John C. Sheehan, who in 1957 chemically synthesized penicillin, a feat that had been thought impossible, died March 21 of congestive heart failure at his home in Key Biscayne, Fla. He was 76 years old.
Sheehan, a professor of organic chemistry, emeritus, at the Massachusetts Institute of Technology, taught at that school for 31 years. He joined the faculty there as an assistant professor in 1946 and in 1948 began working on the synthesis of penicillin. The formation of a just small amount of natural penicillin from mold took months, which proved inefficient during World War II, when demand for the antibiotic escalated.
Sheehan worked for nine years on penicillin synthesis. His work made possible the creation of different, bacteria- specific penicillin drugs. Eventually, improvements in fermentation technology made possible the commercial production of penicillin.
Sheehan was the discoverer of ampicillin, a semisynthetic penicillin taken orally. His research also focused...