John C. Sheehan; Developed Synthetic Penicillin

John C. Sheehan, 76, whose development of synthetic penicillin has been credited with saving millions of lives. Sheehan was a professor emeritus at the Massachusetts Institute of Technology who also was a science adviser to Presidents John F. Kennedy and Lyndon B. Johnson. His 1957 invention solved one of the most baffling problems of modern chemistry, highlighted during World War II when penicillin was desperately needed but took months to produce through the natural mold process. Sheehan’s chemical synthesis led to the development of many tailor-made forms of penicillin to treat a variety of diseases. One of his inventions was ampicillin, a semisynthetic penicillin taken orally. During World War II, scientists had worked for years but failed to synthesize penicillin, and most chemists had concluded that the task was impossible. Harvard University chemistry professor E.J. Corey, a Nobel Prize winner, described Sheehan, his mentor at MIT, as “the undisputed pioneer in the field of penicillin chemistry.� On Saturday in Key Biscayne, Fla., of cancer.