Leopold Ruzicka Nobel Prize in Chemistry 1939

were presented in the laureates’ home birth, and this bond even determined countries. The celebrations for Leopold the first research he conducted in Zu- Ruzicka took place on the morning of rich: His adviser, Hermann Staudinger, 16 January 1940, in the main lecture hall proposed an analysis of “Dalmatian in- at ETH Zurich, where the Swedish am- sect powder.” Ruzicka, who was born bassador, on behalf of the King of Swe- in 1887 in the little town of Vukovar, den, presented Ruzicka with the Nobel then part of the Habsburg Empire, medal and diploma. At the invitation was able to obtain the raw material of the president of the ETH board of of the powder, the blossoms of a va- directors, the guests afterwards enjoyed riety of chrysanthemum, through his lunch at the Restaurant Huguenin on relations in Dalmatia. Staudinger and Bahnhofstrasse. The president of the Ruzicka were the first to identify in University of Zurich and colleagues the blossoms the active ingredients of Nobel Prize in Chemistry 1939 from the University’s chemistry depart- the insecticide pyrethrum, which re- “for his work on polymethylenes ment also joined the party, as Ruzicka mains today one of the most important and higher terpenes” had earned the authority to teach (venia biological insecticides. Cockroaches

legendi) at both institutions. Before his * 13.9. 1887 in Vukovar (now in Croatia) professorship at ETH, he had taught † 26. 9. 1976 in Zurich Ruzicka’s legendary work ethic and researched for some years as a Pri- was reflected by his motto: 1920–1925 Privatdozent at vatdozent at the University. “Academic freedom consists in the University of Zurich Ruzicka received his award for his being allowed to work far work on polymethylenes and terpenes, harder than prescribed.” the scientific names for odorous sub- stances that, in nature, are produced by plants and animals. Ruzicka succeeded served as the experimental animals, in identifying their structures and and legend has it that, decades later, finding ways of synthesizing them – their progeny were still to be found Of Perfumes research that was important for schol- infesting the cellars of the ETH chem- arship and lucrative for the perfume istry building. and Partisans industry. When holding the laureate’s It was Hermann Staudinger who Mid-January in 1940 was bitterly cold traditional acceptance speech, Ruzicka originally brought Ruzicka to Zurich. in Europe. It was a time to shudder, took the opportunity to reflect on his Previously Ruzicka’s doctoral super- both meteorologically and politically. career. He still saw himself as the “ea- visor at the Technische Hochschule Fighting had broken out in various ger and hard-working young chemist Karlsruhe, Staudinger took the gifted parts of the world in the wake of the of 30 years ago, whose path led from and industrious young man with him German invasion of Poland, in Septem- Croatia to Switzerland, where, without as his assistant upon being appointed ber 1939. Because travel was drastically ever forgetting the land of his birth, he professor of general chemistry at ETH restricted, for the first time no central discovered a beloved new home.” in 1912. The relationship with the dom- celebration for the Nobel Prizes was Leopold Ruzicka indeed retained a inant Staudinger broke down in 1916, held in Stockholm. Instead, the awards lifelong connection with his country of however, when Ruzicka chose his own

www.nobelpreis.uzh.ch/en_ruzicka.html Leopold Ruzicka – Nobel Prize in Chemistry 1939 1/4 area of research for his habilitation. “Rutsch,” as he was known to his stu- lab, Ruzicka also requested that signifi- This decision also triggered a conflict dents, was utterly devoted to his subject. cant investments be made to renew the with the president of the ETH board of Small in stature, he was an assiduous increasingly outdated infrastructure. directors, and Ruzicka consequently and skillful researcher who served as There then followed ten years of inten- lost his assistant’s position. Ruzicka a role model to his colleagues and stu- sive and successful research. Ruzicka now needed a new source of income to dents. Upon learning that Staudinger benefitted from his research experi- provide for himself and his wife, Anna, would retire in 1926, Ruzicka applied ence in the perfume industry, and he whom he had married in Karlsruhe. for the succession at ETH. Paul Kar- succeeded in identifying the structure Salvation came through his work in the rer, who himself had been approached, of many complex natural substances, private sector. In 1921, after approach- supported his colleague’s candidature. including steroids. He was also able to ing various companies that manufac- Despite Karrer’s recommendation, the synthesize the male sexual hormones tured fragrances, Ruzicka found a reli- young and eloquent lecturer Richard androsterone and testosterone. In 1939, able partner in Naef & Cie. in Geneva, Kuhn, from Munich, was named to Ruzicka was awarded the Nobel Prize now known as Firmenich. He analyzed the chair. Because Ruzicka believed his in recognition of his work. the odorous substances produced by chances in Zurich would be blocked During the Second World War, Ru- the civet cat and the musk deer, both for some time to come, he accepted zicka was a staunch supporter of both valuable to the perfume industry, and his new home country and the country was able to define their chemical struc- of his birth. He served for two years in Ruzicka succeeded in ture. In the process, he made a sensa- the Swiss Army, was active in assisting synthesizing the male sexual tional discovery: 17-membered carbon refugees, and gave chemistry lessons hormones androsterone rings. Up to then, chemists had ques- to interned Polish students at Winter- and testosterone. tioned the existence of such large com- thur’s technical school. He also sup- pounds. He also succeeded in creating ported Josip Broz Tito’s Communist synthesized carbocycles, thus allowing an ­appointment at the University of partisans, who were fighting against the materials to be mass produced at ­Utrecht in 1927. Nevertheless, Ruzicka’s the German and Italian occupying low cost. Following these successes, stay in Holland would be short: Rich- powers in the Balkans. As part of this Ruzicka’s name became increasingly ard Kuhn left Zurich after just three endeavor, Ruzicka founded the “Yugo- well-known in professional circles. years, and the professorship was again slavian-Swiss Aid Committee,” which Ruzicka moved to Geneva in 1926 vacant. Karrer successfully applied his he also presided. His skillful lobby- as a research associate of the fragrance influence on the appointment commit- ing ensured that part of the post-war company. That he found himself back tee, now led by the the new president Swiss aid reserved for neighboring at ETH, as a professor, three years Arthur Rohn, and Ruzicka could finally countries would also benefit the new later was due to a change of leader- return to ETH. state of Yugoslavia. Upon becoming ship at that institution and thanks to Upon his appointment in 1929, Leo- head of state, Marshal Tito rewarded some friendly support from the “com- pold Ruzicka became the first Swiss Ruzicka with his personal friendship petition” at the University of Zurich. citizen to hold the chair for general and a medal of honor. Ruzicka had taught at ETH since 1918 chemistry at ETH since its establish- The changes in global politics were and, from 1920, also at the University, ment in 1855. He had acquired citizen- reflected at the chemistry lab. In the where he had earned the respect of ship in Zurich in 1918 and, unlike his 1930s, Ruzicka had many doctoral stu- Paul Karrer, the head of the Depart- predecessor, was determined to settle dents, including Tadeus Reichstein, but ment of Chemistry. Both Ruzicka’s tal- in Zurich. Accordingly, after his ap- after the war began, many of Ruzicka’s ent and his work ethic were legendary: pointment he immediately purchased staff emigrated to America. A new col- He lived by his motto that “academic a plot of land at Freudenbergstrasse league came from eastern Europe in freedom consists in being allowed to 101 and built a house on it, complete the person of his subsequent succes- work far harder than prescribed.” with a large garden. At the chemistry sor, Vladimir Prelog. After the war,

www.nobelpreis.uzh.ch/en_ruzicka.html Leopold Ruzicka – Nobel Prize in Chemistry 1939 2/4 chemistry was once again a highly- Made in Zurich: that “odorous substances have made no sought subject, and student num- The Biggest small contribution to the methodological, bers rose sharply. Ruzicka, however, Carbon Rings systematic, and theoretical aspects of the restricted himself to administrative development of general organic chemistry.” leadership for a time. Shortly after the Flower scents and essential oils are among But Ruzicka was not only “Lord of the war, he used the income from Amer- the most pleasant fragrances the world has Carbon Rings”; in the 1930s, he was also ican hormone patents to establish a to offer. In chemical terms, they are mole- at the forefront of hormone research. He foundation and, with the help of the cules produced by plants. When we inhale recognized the close chemical relationship funds, built up an exquisite collection them, they activate our olfactory cells. between the higher terpenes and the ster- of Dutch painting. Leopold Ruzicka Animals also produce odors that serve for oids, and he isolated the male sex hormone became a connoisseur of art and be- reproduction or the defense of territory. androsterone almost simultaneously with queathed his collection to the Zurich Chemically, these substances are often re- the German chemist Adolf Butenandt, who Kunsthaus. The postwar period also lated to one another, and many belong to had already discovered the female sex hor- brought change to Ruzicka’s personal the class of terpenes. The name comes from mone estrogen. Accordingly, the Nobel Prize life: His first marriage ended in divorce turpentine, a resin long used in painting. Committee divided the Chemistry Prize for in 1950, and a year later he married his There are over 8,000 known terpenes. 1939 between Ruzicka und Butenandt, with secretary. Characteristic of these substances are the German chemist being explicitly hon- Leopold Ruzicka retired in 1957, but ring-shape molecules; several rings are of- ored for his hormone research, while the there was still much for him to do. In his ten interlocked, similar to honeycombs. But Swiss was singled out for his discoveries how large can a single ring be? The best- in the domain of odors. Through his close known is the benzene ring, which contains cooperation with Ciba in Basel, Ruzicka also In the Second World War, six carbon atoms linked in a regular hexa- played a significant role in the growth and Ruzicka supported the gon. Before Ruzicka’s work, rings with three prosperity of the chemical industry in Swit- Communist partisans who were to eight members had been discovered or zerland. (MW) fighting against the German produced in the laboratory. But because and Italian occupying powers researchers had failed to achieve larger in the Balkans. numbers of members, it was believed that such rings were energetically impossible. sunny garden at ­Freudenbergstrasse Between 1921 and 1923, however, Ruzicka 101, he cultivated a variety of alpine demonstrated the existence of rings with 15, plants. He loved roses – indeed, and even 17 members. He discovered them ­Ruzicka means “little rose” in Czech in moscine and civetone – the main odorous – and loved photographing them. substances of the musk deer and the civet He even once described himself as a cat – which were used in the perfume indus- rose without thorns, which may be try. Ruzicka also succeeded in synthesizing something of a misnomer for the self- these substances, thus supplying Naef & confident professor with a good feel for Cie. with raw materials that could be pro- power. Ruzicka regularly nominated duced in large quantities for their perfumes. chemists for the Nobel Prize, and only In further experiments, Ruzicka even two of his recommendations failed to succeeded in producing molecular rings be awarded the prize. Margrit Wyder with up to 34 members, an achievement that necessitated the revision of several the- Einstein und Co. – Source: Margrit Wyder: ories on atomic bonding. In an article for Nobelpreisträger in Zürich; Verlag NZZ libro, Zürich 2015 Illustration: Aline Telek the fiftieth anniversary of Naef & Cie., now Translation: University of Zurich known as Firmenich, Ruzicka emphasized

www.nobelpreis.uzh.ch/en_ruzicka.html Leopold Ruzicka – Nobel Prize in Chemistry 1939 3/4 Leopold Ruzicka researched odorous Leading expert on organic ring compounds: Leopold Ruzicka in the lecture hall. substances and hormones, and served Photo: ETH Library, archives in the Swiss Army in the Second World War. Photo: ETH Library, archives

Completely devoted to his work: Leopold Ruzicka as a young chemist. Photo: ETH Library, archives

www.nobelpreis.uzh.ch/en_ruzicka.html Leopold Ruzicka – Nobel Prize in Chemistry 1939 4/4