Hermann Emil Fischer

Hermann Emil Fischer (Flamersheim, Germany, 9 October, 1852 – Berlin, 15 July 1919)  is one of the founders of classic organic chemistry. He received the 1902 Nobel Prize in chemistry for pioneering work on sugar and purine syntheses.

Life
Fischer was born and raised in Flamersheim (part of Euskirchen near Cologne) in North-Rhine-Westphalia. In 1869 he received his high-school diploma and after a non-finished education in business, he switched fields and went in 1871 to the University of Bonn to study chemistry. After a year he continued his studies at the newly established University of Strasbourg, where he received his doctorate under Adolf von Baeyer in 1874. His topic was the study of phenolphtalein dyes. In 1875 he accompanied his supervisor to Munich, where,  three years later, he made his habilitation (second doctor's degree) and became Privatdozent. In 1879 he was promoted to associate professor of analytic chemistry. In 1881 he was appointed professor of chemistry at the University of Erlangen and from 1888 until 1892 he was professor of chemistry at the University of Würzburg. In 1892 he went to the Friedrich-Wilhelms-Universität (University of Berlin), where he remained until his death in 1919. He died by his own hand after he was told that he had cancer and had lost two of his three sons during the war. Fischer was instrumental in the founding of the Kaiser-Wilhelm-Institut für physikalische Chemie und Elektrochemie (KWI), since 1953 called Fritz-Haber-Institut der Max-Planck-Gesellschaft.

In 1888 Fischer married Agnes Gerlach, who died seven years after their wedding. They had three sons, one of whom was killed in World War I; another took his own life at the age of 25 as a result of compulsory military training. The third son, Hermann Otto Laurenz Fischer, who died in 1960, was professor of biochemistry in the University of California at Berkeley.

Work
In 1875, Fischer, while still in Strasbourg, published his first great discovery: the compound phenylhydrazine. Fischer started his research on the purines in 1881. He determined the structures of uric acid, xanthine, caffeine, theobromine, and other related compounds, and he showed that they are all derivatives of a single compound, a nitrogenous base that he named purine.

His researches into the sugar group, begun in 1883, were of great importance to organic chemistry. In 1884 he found that phenylhydrazine reacts with simple sugars to form derivatives called osazones. Despite major complications because of stereochemical relations, Fischer was able to use these derivatives to determine the molecular structures of fructose, glucose, and many other sugars, and he was able to verify his results by synthesizing those compounds. He also showed how to distinguish the formulas of the 16 stereoisometric glucoses. In the course of his stereochemical research, Fischer discovered that there are two series of sugars, the D sugars (dextrorotary, right-handed) and the L sugars (levorotary, left-handed), that are mirror images of each other. His study of sugars led him to investigate the reactions and substances involved in fermentation, and, in his investigations of how enzymes break down sugars, Fischer laid the foundations for enzyme chemistry.

Fischer's researches ultimately elucidated the structure of proteins. It was already known that proteins were composed of amino acids, but Fischer found new ways of purifying amino acids and determining how they are combined together within the protein molecule. He then found ways to link amino acids to each other and began synthesizing protein-like substances; in 1907 he was able to combine 18 amino acids into a polypeptide, which he then broke down by enzymes in the same manner as would occur in a natural protein.

Heritage
Fischer's name lives on in the following chemical processes


 * Fischer indole synthesis
 * Fischer projection
 * Fischer oxazole synthesis
 * Fischer peptide synthesis
 * Fischer phenylhydrazine and oxazone reaction
 * Fischer reduction
 * Fischer-Speier esterification
 * Fischer glycosidation

The Fischer-Tropsch process is named after Franz Emil Fischer (1877 – 1947).