Vitamin B12 has a long history of development that began in the early 1920s. At that time, the American pathologist Whipple was trying to find out which active ingredients can be found in raw liver because they were proven to be responsible for curing fatal anemia in dogs.
In the course of this, Murphy and Minot, two American doctors, discovered an antipernicious factor in 1926, which also had an effect on humans and received a Nobel Prize in 1934 together with Whipple. This has long been the vitamin B12 known today, which was isolated for the first time in 1948.
This was achieved independently by both a British team of researchers led by chemist Lester Smith and a group of biochemists led by Karl A. Volkers from America. The molecular structure of vitamin B12 was subsequently discovered in 1955 using X-ray diffraction, whereupon the responsible biochemist Dorothy C. Hodgkin received a Nobel Prize in 1994.
In 1972, this resulted in the total synthesis of vitamin B12, which is why this vitamin is considered to be the largest possible molecule that occurs among the totally synthesized substances.