Biography & Contributions
Hermann Emil Louis Fischer was a German chemist and Nobel laureate born on October 09, 1852 – died on July 15, 1919.
Fischer’s researches included the discovery of phenylhydrazine drug compound. By 1878 he figured out the chemical formula for phenylhydrazine, and this discovery stimulated other researches leading to the development of such synthetic drugs as novocaine. In 1881 Fischer began investigations into a new field, purine chemistry, identifying three amino acids and synthesizing many more. This research resulted in many more advances in the German drug industry. He also discovered the Fischer esterification and developed the Fischer projection, a symbolic way of drawing asymmetric carbon atoms.
Fischer studied the active principles of tea, coffee and cocoa, namely, caffeine and theobromine. In 1884 Fischer began his great work on the sugars, which transformed the knowledge of these compounds.
Even before 1880, the aldehyde formula of glucose had been indicated, but Fischer established it by a series of transformations such as oxidation into aldonic acid and the action of phenylhydrazine which he had discovered and which made possible the formation of the phenylhydrazones and the osazones.
By passage to a common osazone, he established the relation between glucose, fructose and mannose, which he discovered in 1888. In 1890, by epimerization between gluconic and mannonic acids, he established the stereochemical and isomeric nature of the sugars.
Fischer established the stereochemical configuration of all the known sugars and exactly foretold the possible isomers. His greatest success was his synthesis of glucose, fructose and mannose in 1890, starting from glycerol.
He sought effective analytical methods of separating and identifying the individual amino acids, discovering a new type, the cyclic amino acids: proline and hydroxyproline. Fischer also studied the synthesis of proteins by obtaining the various amino acids in an optically active form in order to unite them. He was able to establish the type of bond that would connect them together in chains, namely, the peptide bond, and by means of this he obtained the dipeptides and later the tripeptides and polypeptides. In 1901 Fischer discovered, in collaboration with Ernest Fourneau, the synthesis of the dipeptide, glycylglycine, and in that year he also published his work on the hydrolysis of casein.
His synthesis of the oligopeptides culminated in an octodecapeptide, which had many characteristics of natural proteins.
Fischer also studied the enzymes and the chemical substances in the lichens. In 1890, he also proposed a "Lock and Key Model" to visualize the substrate and enzyme interaction.
Fischer is noted for his work on sugars among other work the organic synthesis of (+) glucose and purines. He was also instrumental in the discovery of barbiturates.
Fischer Esterification
Fischer Esterification is a special type of esterification by refluxing a carboxylic acid and an alcohol in the presence of an acid catalyst. Commonly used catalysts for a Fischer esterification include sulfuric acid, tosylic acid, and Lewis acids such as scandium (III) triflate.
Fischer Projection
Fischer Projection is a two-dimensional representation of a three-dimensional organic molecule by projection. Fischer projections are most commonly used in biochemistry and organic chemistry to represent monosaccharides, but can also be used for amino acids or for other organic molecules.
Read More: Fischer Esterification Reaction
No comments:
Post a Comment