Conrad Eugster studied chemistry at the University of Zurich, received his doctorate here in 1953 under the guidance of Paul Karrer, and became a Privatdozent in 1955. He was an academic guest at the University of Illinois in 1961. In 1963 he was appointed Associate Professor, and in 1969 became Full Professor of organic chemistry in the Institute of Organic Chemistry, where he remained until his retirement in 1988.
The main focus of Conrad Eugster's research efforts was in natural product chemistry, particularly the isolation, structure elucidation and synthesis of new natural products. He made important contributions to the field of alkaloid chemistry through the discovery of macrocyclic spermidine alkaloids, the determination of their absolute configuration and their synthesis. New natural products isolated from fungi include muscarine, muscimol, muscazone and ibotenic acid. Conrad Eugster also studied intensively the chemistry of quinones, including the isolation and structure determination of caryopterone, cordeauxiaquinone, and the reactions of quinones with nucleophiles for the synthesis of annelated quinones. He made important contributions to the area of terpene and carotenoid chemistry; together with Peter Rüedi a large number of coloured tetra- and pentacyclic abietanoids were isolated from tropical plants of the Labiatae family, and the first syntheses of B,B-carotene and related carotenoids was completed in collaboration with Paul Karrer. Further work in this area included the determination of the absolute configuration of a-ionone, g-ionone, B,e-carotene, luteine as well as their 5,6- and 5,8-epoxides and 5,6-dihydroxy derivatives. Apart from these and other contributions to natural product chemistry, Conrad Eugster also researched the chemistry of heterocyclic systems, in particular derivatives of furan of interest as flavour chemicals, the synthesis of cyclohexylsulfonic acids, and last but not least, the mechanism of the Favorskii rearrangement.