Russell Earl Marker (March 12, 1902 – March 3, 1995) was an American chemist who invented the octane rating system when he was working at the Ethyl Corporation. Later in his career, he went on to found a steroid industry in Mexico when he successfully made semisynthetic progesterone from chemical constituents found in Mexican yams in a process known as Marker degradation. This eventually led to the development at Syntex of the combined oral contraceptive pill and synthetic cortisone - and to the development of the Mexican barbasco trade.
He was born on March 12, 1902 in Hagerstown, Maryland. He received his B.S. in 1923 from the University of Maryland and an M.S. in physical chemistry in 1924 from the same institution.
In 1926, he married Mildred Collins (1899–1985) and worked as an analytical chemist at the Naval Powder Factory in Indian Head, Maryland. He then began work at the Ethyl Corporation where he came up with the concept of the octane rating.
In 1938, he proposed a new molecular structure for sarsasapogenin where the side chain was chemically reactive due to the two oxygen atoms connected to the same carbon. The newly found reactivity of the side chain can be used to remove most of the atoms in the side chain. After most of the atoms are removed from the side chain, a steroid ring is left. After a few chemical modifications, a steroid ring can lead to the creation of progesterone. This was the first practical synthesis of progesterone. It was also a precursor in the preparation of cortisone.