Wieland, Heinrich Otto
WIELAND, HEINRICH OTTO
(b. Pforzheim, Germany, 4 June 1877; d. Starnberg, Germany, 5 August 1957)
Wieland was the son of Theodor Wieland, a pharmaceutical chemist. He studied chemistry at the University of Munich in 1896, the University of Berlin in 1897, and at the Technische Hochschule at Stuttgart in 1898. The following years he returned to Munich and in 1901 received the Ph. D. for his research in organic chemistry under the direction of Johannes Thiele. In 1904 Wieland was appointed Privatdozent at the University of Munich and in 913 received a senior lectureship in organic chemistry He remained at Munich until 1917, during which time he devoted his research chiefly to the chemistry of organic nitrogen compounds.
Wielands’s earliest work concerned the mechanism of addition of the oxides of nitrogen to olefins and the mechanism of the nitration of aromatic hydrocarbons. He was able to isolate the intermediate nitro compounds and show the similarity between the two classes of reactions. At this time Wieland also undertook a study of fulminic acid, and in a review published in 1909 he summarized his investigations of its polymerization and its step-by-step synthesis from ethanol and nitric acid.
Wieland’s most significant work during his early career was the chemistry of the hydrazines, a project that led him to the discovery of the first known nitrogen free radicals. In 1911 Wieland prepared tetraphenylhydrazine from the oxidation of diphenylamine. He showed that when heated in toluene, tetraphenylhydrazine dissociates into two diphenylnitrogen free radicals, characterized by the green color that they impart to the solution. Wieland then undertook an extensive study of the effect of ring substituents on the production of radicals from substituted tetraphenylhydrazines.
In 1917 Wieland accepted a position at the Technische Hochschule in Munich, but during 1917–1918 was given a leave of absence to take part in chemical warfare research under the direction of Fritz Haber at the Kaiser-Whilem Institute in Berlin-Dahlem. After the war Wieland returned to the Technische Hochschule in Munich, where he remained until 1921, when he accepted a position at the University of Freiburg. In 1924 Willstätter resigned his post as director of the famous Baeyer laboratory at the University of Munich and recommended Wieland to be his successor. Wieland returned to Munich in 1925 and directed the Baeyer laboratory for twenty-five years until his appointment as emeritus professor in 1950. During this time he became more interested in the structural determination of natural products. He had already shown considerable interest in biochemistry, for in 1912 he first proposed his theory of biological oxidation. In his subsequent studies on the mechanisms of oxidation reactions published in over fifty papers from 1912 to 1943, Wieland was able to demonstrate that many biological oxidation reactions proceed through dehydrogenation. While director of the Baeyer laboratory wieland and his students worked on the isolation and structural determination of many natural products, including morphine alkaloids, lobeline alkaloids, strychnine alkaloids, pterins that the first isolated from butterfly pigments, mushroom poisons, and cardioactive toad poisons.
Wielands’s best-known work, however,concerned the structure of bile acids, for which he received the 1927 Nobel Prize in chemistry. Wieland’s research on his this subject began in 1912,and for twenty years he and his collaborators sought to gain insight into the complicated structure of cholic acid and other bile acids related to cholesterol, through oxidation of specific portions of the molecule. Gradually information was assembled from such studies performed by Wieland’s research group and also those carried out by other chemists, especially windaus, who received the 1928 Nobel prize for his work on the constructions of sterols. The following structures wer5e generally accepted for cholic acid and cholesterol when Wieland and Windaus presented their Nobel lectures on 12 December 1928. Only two carbon atoms (numbered 15 and 16) remained to be assigned with certainly, and they were provisionally placed on carbon atom number 10, as shown.
During the next four years Wieland and his coworkers at Munich tried to establish the location of
these two carbon atoms, yet they met with little success. In 1932 new evidence of the molecular size of steroids, gained from X-ray crystallographic analysis, cast doubt on the basic structure. By reconsidering the data collected over the previous twenty years, Wieland and the British chemists O. Rosenheim and H. King independently arrived at the presently accepted structure of cholic acid.
Wieland’s research continued until his retirement in 1950. He served as editor of the Annalen der chemie for over twenty years and received the Otto Hahn Prize in 1955.
I. Original Works. Wieland published over 350 papers and several books, which listed in poggendorff, V, 1366–1367: VI, 2876–2877; VII, 985–987. Some of his most important publications are “Die Knallsäure,” in Sammlung chemischer und chemisch-tech-nischer Vorträge14 (1909), 385–461: Die Hydrazine (stuttgart, 1931); “Die Chemie der Gallensäuren,” in Zeitschrift für angewandte Chemie und Zentrablatt für technische Chemie, 42 (1929),421–424; “Recent Researches on Biological Oxidation,” in Journal of the Chemical Socity (1931), 1055–1064; On the Merchanism of Oxidation (New Haven, Conn., 1932); and “Die konstitution der Gallensauren,” in Berichte der Deutschen chemischen Gesellschaft67 (1934), 27–39.
II. Secondary Literature. An authobiographical sketch appeared in Nachrichten aus Chemie und Technik (1955), 222–223. A useful summary of his work as a tribute on his 65th birthday was given by Elisabeth Dane, “Die Arbeiten H. Wieland auf dem Gebiet der Steroide,” in Die Naturwissenschaften, 30 (1942), 333– 342; Wilhelm Franke, “H. Wielands Arbeiten zum Mechanismus der biologischen Oxydation,” ibdi., 342– 351; Friendrich Klages, “Die Stickstoffarbeiten von H. Wieland,” ibdi., 351–359; and Clemans Schöpf, “Die Arbeiten Heinrich Wielands über stickstoffhaltige Naturstoffe (Alkaloide und Pterine),” ibid., 359–373.
Other accounts inculde Rolf Huisigen, “The Wieland Memorial Lecture,” in Proceedings of the Chemical Socity (1958), 210–219; Gulbrand Lunde, “The 1927 and 1928 Nobel Chemistry Prize Winners, Wieland and Windaus,” in Journal of Chemical Education, 7 (1930), 1763–1771; and Adolph Windaus, “The Chemistry of the Sterols, Bile Acids, and Other Cyclic Constituents of Natural Fats and Oils,” in Annual Review of Biochemistry, 1 (1932), 109–134.
Daniel P. Jones