Complex sentence: In 1963, he was sole author of a classic paper in the Journal of the American Chemical Society in which he reported a method he called solid phase peptide synthesis, which is the fifth most cited paper in the journal's history.
Split into simpler sentences: In 1963, he was sole author of a classic paper in the "Journal of the American Chemical Society" in which he reported a method he called "solid phase peptide synthesis". This article is the fifth most cited paper in the journal's history.